I have a Rotel RX 802 which was given to us by a relative along with some Leak Speakers and a dual 504 turntable. All which were used together but have been in storage for at least 5 years.



We've spent weeks trying to get it all working; sometimes it works fine (and sounds amazing!) and other times it doesnt, so I'm thinking its a connection issue somewhere. We've replaced the speaker wires and the 2pin and 5pin connectors.

The issues that we have are (sometimes individually and sometimes all at the same time),

1.) A buzzing on 1 or both speakers
2.) 1 or both speakers not working
3.) 1 speaker louder than the other
4.) Speakers working but playing very quietly

We love the equipment and really want to get it working rather than buying new!

I have only owned these speakers for a couple of days and i went to try them with a movie today and they started to make a buzzing noise with a car with a loud exhaust-it plays pop music etc fine, but from my very limited understanding there is a coil loose or delaminated which can be re glued with the right adhesive?

Hello everyone,
I'm recently playing with the design of my next phono amplifier I called Zenigata's phono. I put here the LTspice files and it would be nice if someone could revise it but also commenta are welcome.



Here you are the distorsion at 350mVrms output: just a -105dB 3rd armonic


The signal / noise ratio is about 85dB and the RIAA matching id +/- 15mdB

HELLO ,
Does anybody have a schematic for FIDEK-FPA12A,(I have one for fidek fpa10a , but i don't know if they have similar schematic) I have this amplifier and i have a problem with one chanel , It makes a strange sound , like a buzz.If someone want's the fidek fpa 10a schematic ,send me a PM.








---------------------------------------------------------------------------------
SORY for my english

My audio chain consists of a USB DAC -> Active Filter -> Amplifiers -> Speakers.
There are frequent power failures, that result in a loud bang that could potentially damage my ears and the speakers. I suspect that the USB DAC is the culprit. The USB DAC is powered by a 5V linear PS.
I was wondering if a relay to short out the outputs of the USB DAC on a power failure would limit the damage. I can introduce a 100 ohm resistor in the shorted paths to limit the output current.
The 5V relay I am considering is the Omron G5V-1 (5V, 30 ma, 176 ohms).
Can you please review my scheme and suggest improvements? The zener diode will be 3.6V in the implementation.
Thanks

Hey fellow Aussies!

I haven't seen any recent posts here regarding use of the current (June 2019) range of Jaycar speaker components / drivers / woofers / tweeters so I thought I'd see if there was any interest out there still for people wanting to DIY build some speakers using this 'response' range of products?

I started an idea and build 2.5 years ago and after many changes (with large gaps in between) I finally have a recipe for a speaker I'm proud of and does what I intended it to do!

Short version: ~50L ported enclosure using Jaycar CT2007 1" Tweeter and Jaycar CW2194 6.5" Woofer, tuned to F3 of 33Hz. Designed for enjoying both Movies AND Music without the requirement of a subwoofer.

YES, I do have a sub and love my bass but I also have a 2.5 yr old toddler so I still wanted speakers I could enjoy while he sleeps. These speakers walk the line between not enough and too much low end so you can use them as-is and still enjoy but the sub is always there if need be. Are they reference monitor flat response? No, and they were never meant to be. Are they fun and enjoyable to use for movies and music? Absolutely! 🙂





I haven't arranged anything yet (I can if need) but I thought I'd gauge some interest if there was anyone out there looking to build something like this and if they were keen on some plans/designs so they'd have the info they need to build their own?

If you've built something similar then please share as I'd love to see your creations from also using the Jaycar drivers 🙂

I used my B&K LCR meter to measure impedance of the three drivers in my speakers. I disconnected the spearker wires from the outboard XO and connected the meter leads to the wires. Meter showed 4.5ohm for tweeter, 8.2 for mid and 21.3 for woofer. 21.3 seemed vey odd so I calibrated the meter and then tested it on some resistors. Results were accurate and matched resistors markings. The speakers sound very good and the bass is well balanced with the other drivers. How could woofer have 21.3ohm impedance?

Khadas Tone Board output impedance = 100ohm
NC122MP input impedance = 47Kohm

If I'm not mistaken, something around 10k impedance should be appropriate.

The cheapest, simplest (decent) option I came up with is an ALPS RK27. But I know there are other possibilities.
There are some relay attenuators out there that promise to be quite transparent (and I've always been a fan of the sound of relays clicking)
Or step resistors. Khozmo if I decide I've got too much money.
Or should I go with a chip-based solution? PGA2310 or Muses maybe? I've been trying to settle on something for the last couple of days while I'm laid up sick on the couch, and I'm pretty sure I'm overthinking it at this point.

What would you go with?
Thanks for any input.

Here's a layout of my build to give an idea of the space I've got to work with.

As an aside, I've ordered this chassis for my build. Does anyone have an opinion on whether the radiator fins would be sufficient for the Hypex or do I want to be drilling ventilation holes?

Hi,

I am selling a Purifi Black alu GX285 Amplifier.
Made with a great care and good components.
The amp is like new and come with 2x PURIFI 1ET400A and one HYPEX SMPS1200A400 PSU.
The Buffer has Full balanced inputs with DIP8 OP Amps, you can update it. I put some OPA1656 (THD + N @ 1 kHz : 0.000029%) inside.
OPA2210 is another great alternative and sounds even better )

I ship for free in EU only
Paypal only please

PRICE : 1060€


Measures :

1W, f=1kHz 0.0007 %
10W, f=1kHz 0.00026 %
100W, f=1kHz 0.00015 %
1W, f=20-20kHz 0.0007 %
10W, f=20-20kHz 0.00029 %
100W, f=20-20kHz 0.00017 %

Buffer spec :

• THD: 0,00026% @ Vin 2,5 V RMS
• GAIN: 14 dB
• BANDWIDTH: 2 Hz - 150 kHz
• SLEW RATE: 24 V/uS
• CMRR: > 100 dB @ 60 Hz
• DYNAMIC RANGE: 127 dB
• INPUT IMPEDANCE: 47 Kohm
• NOISE AND HUM: 6 uV
• SIZE : 62mm x63mm
• OP AMPS : OPA1665 (DIP 8)
• POWER SUPPLY: +-12V TO +-18V

Looking for circuit simulator and design software that has all components for an advanced cinema sound processor design. I have the design drawn up in sections on paper and the rest in my head. Need software that I can see the current path and the outputs easily. Preferably free but not absolutely required. No online monthly services. Please list the pros and cons to use such software for this endeavor. Thank you.

Friends, I found a 0dB amplifier circuit diagram on the Internet.
How about this schematic diagram? Can it be directly applied

Hola, por favor alguien me podría ayudar a saber que número de pieza es el Q512 o su hoja de datos, busque en google pero no encontré información, el amplificador es un Jl audio slash 500/1

hi, I need a regulated 42VDC for a project I am working on, ordered a 30V trans, which when arrived gave 33V so through my regulator i go 48 VDC, which is to high for my circuit. the standard LM317 on works up to 25 VDC, not high enough. Then I found this unit, the LM317HVT, the spec sheet says can go up to 58 VDC out or so.
the question is if I buy a kit from F/Bay for a LM317 & upgrade the capacitors to say 60-100V, can I simply replace the two regulators, the hopefull adjust insert the unit between my Tans & current ultra low noise regulator & adjust the DV voltage down to 42 VDC?

Cheers

How is everyone supplying power to their Minidsp?

I trialled using the USB port on my Blu Ray player and it seems to work. The player is set up on a home network and powers up when I select it from the wifi remote.

It doesn't seem to introduce any noise either.

This last year I decided on a change from audio projects and got into some model railway digital control projects.
Designed a shuttle, station start stop and digital controller and all worked well.
On the second revision of pcb's I decided to improve the noise rejection of the power supply on the digital controller.
I separated the motor driver 12 volts and the microcontroller 12 volt (pre reg) supply with diodes.
Worked on the bench ok but first customer to buy one had trouble within half an hour with motor driver IC blowing up.

So back to the drawing board. I went through motor driver datasheet again and it had a note about power supply needing to be solid to absorb flyback spikes from motor.
Of course one of the diodes now disconnected the previous capacitor and there was noise on power supply.
Luckily there was a hole in the pcb for ground near where I needed a cap and I put it in there for one leg and soldered other leg to power supply diode.

I guess the moral of the story is to think more carefully about changes and there consequences.

DYMO goes back to 1958. By 1964 they were running ads in specialty magazines.

Does anyone know the specs for a zapco M80? Can't find anything on it. Is it a cheater amp and how low of a load will it handle?

I have the GFA-7805 & 7807 that have kind of a weird anomaly when the 12 volt trigger is connected and the preamp is turned off. All the thermal protection lights are on until the preamp is selected on which then sends the 12 volt trigger signal to the Amplifiers to turn on then the all the thermal protection lights go out after a short 10 seconds, and the relays turn on and sound comes out. These amps are new to me and I have gone through them repairing the timing caps around the 555 timers and replacing some of the outputs in 1 channel in one amp and 1 channel in the other. The only time I noticed this strange anomaly was when i hooked up the 12 volt trigger lines and with the preamp off and amplifiers selected on, but with no 12 volt trigger selected all the thermal protection lights are on and that's a lot of red lights in a dark room. I suspect the standby power supply has an issue. I bought 1 amp from one part of the USA, and the other from another part of the USA. No schematics out there in the wild, but its not to hard to troubleshoot. was just wondering is this the norm for these amplifiers before I get back into them. thanks. Any help appreciated.....

Hello,

I have been a diyAudio member for more than 15 years, user ID: 355f1. Email: vignale.355f1@yahoo.com. The system tells me that I do not have privileges, it does not send me any communications even to reset my password, nothing.

I contacted the forum management but to no avail. I had to register under a different email address.

I need help from the moderators.

Thank you

I have no experience with planar speakers only electrostatics which i know are power hungry can anyone enlighte me 🙂

Hi all!

Does anyone know of a suitable driver for Harlech S2s, being the mid driver? front fascia above the tweeter?

Any help or advice would be greatly appreciated.

I need to heat a 5U4G but I don't have a 5V winding, so will need a small separate 5V filament xformer. Would these Triad flatpack dual 5V secondary transformers have enough isolation for the HV?

https://www.farnell.com/datasheets/2279132.pdf

5U4G wants 3 Amps, this little xformer can do 4.8 A @ 5V with dual secondaries in parallel. So the current is covered, I just need confirmation that the HV will be ok here. Is the "hipot test" the measurement I'd be interested in to determine the safety factor one needs in a 5U4 rectifying 280-0-280.

As title suggests, and non of loudspeaker databases cover tweeters...

Im looking for tweeters that have membrane weight (MMS) of 0.3g, low FS <400hz, and it should be cheap ?

Anyone have some recommendations or some actual database i can look this up ?

Looking through my tube stash I see that I have some 1635s. My impression is that they are somewhat like 6N7s but with substantial differences. I did a search here and don't see any discussion of this tube, so I'm curious - does this look useful or not? https://frank.pocnet.net/sheets/049/1/1635.pdf

Have this Hasimoto built amp and it's been working fine for years. Yesterday when I fired it up I noticed that the bias started increasing beyond its 50ma mark. Have a meter on the front. Quickly turned it off and took it to my work bench. Tried to readjust the bias with just the tubes in one channel and got it down to 50ma but now the voltage across the 10ohm cathode resistor measures only 20mv. Measured every other voltage on the amp and they are all according to the schematic. Even switched to another multimeter just to be sure. So now I`m absolutely confused. Never experienced this before.

I have been using the drivetrack as a crossover for over a year now and cannot recommend it more for Martin Logan III owners. Getting the passives out of the way really opens up the bass. I have been through many tweaks on the Logans in this order --have replaced bass drivers (small improvement), got a new bass amp for driving the bass passively through the speaker x-overs (bigger improvement), then bought a driverack for just the bass (wammo this was it). But then I tried actively crossing over my big tube amps for the panels (another step up), then I tried crossing over at 250 hz (versus stock 125), another big step up. Some where in there I applied Greorgehifi's notch circuit on the bass drivers (it's still in).

This is the way to go for ML III owners IMO. But question : has anyone modded the dbx? I see a lot of Behringer 2496 mod projects but nothing for the pa. Appreciate any ideas.

Power supply cooked up, and the component values are not visible anymore.

Does someone has the values or a photo from the burned components?

R234
R231? (Marking burned)
R250
R251? (Marking burned)

The story
A 20 kg heavy amp ended up in my living room. A guy living near me had had it for 10 years when suddenly one channel died and the problem was found to besome resistors going very hot. When he finally had gotten new resistors, he had ruined some of the Cu traces and this is where I enter the scene.
I had offered my help to tidy things up but when the poor owner missed the elevator in my house and had carried the amp, three stairs to my apartment there were some other issues to be addressed and just for fun (well ...) I managed to short either a resistor or a diode.
The main issue is that (amp not hooked to a load) voltages to the power transistors as well as the driver stage is approx 10% higher than stated by the schematic.

To do
Replace the components I may have ruined. Tidy up the area and repair the traces. Replace the old 47uF/35V capacitors next to the transistors Q101/Q113. Screw the monster together.

Schematics and photos:
I have marked out "troubled areas and components".

Gclass-a100d3.pdf

PSU.pdf

This is where I have started. Next some close ups and discussions about the high voltages and excessive heat. But if anyone has some experience with this amp, I will led at least two ears.

Hi all. I recently bought a Pioneer A-616 "Reference Series" amp. It works well with tone bypassed, but has a fault in the tone section as there is severe distortion when it is engaged - probably just the opamp in that section.
Anyway it sounds good this amp! It really blew my Arcam Alpha 8r out of the water. Not much onto on the net about this model but it has good specs. It is however 30 yrs old, and I'd like to know if anyone respects these amps and whether it would be worthwhile re-capping and/or replacing other components?
Alternatively would it be wiser to invest in a another model?
Cheers.

Looking for 2.2uf caps 2of

Mundorf silver in oil
Fostex copper foil

Thanks.

Hello, just completed wc ba2018 line stage. Can anybody recommend a pwr supply and ready to go chassis for this. i just found out i am not very good at drilling holes in metal. i was thinking this from AMB audio

Hi guys, I would like a USB to spdif converter for my PC, with BNC output. Could you give me some advice? On audiophonics I have seen these two products:
https://www.audiophonics.fr/en/diy-...l-interface-usb-384khz-to-i2s-dsd-p-7403.html
https://www.audiophonics.fr/en/diy-...if-bnc-75-ohm-for-amanero-wm8805-p-11487.html

Would they work well enough together, or can I do better for similar price range (such as buying a Topping D10 and modify it replacing the coax output connector with a BNC output)?

Thanks for the help!
Tony

Hi there,
I built a boom box using a TPA3118D2 in a mono setup (input channels strapped together), accepting a signal from a phono jack. The power comes from 6 battery cells with a BMS. So far so good.

Then I decided to add a self-standing audio source and I installed a Raspberry Pi Zero W (Wi-Fi version), also powered by the same battery pack via a DC-DC converter (22V->5V), connected to a DAC . I added a source toggle to be able to switch between line input and RPI.



This created a quite loud interference in the loudspeaker. The interference is audible when both the amp and the RPI are on. The volume doesn't change the intensity of the noise. I noticed that the noise increases with the RPi activity, so I'm guessing that it may be somehow tied to the current draw of the RPi. I don't think it is the WiFi radio signal, or at least not only that, because even commands that cause CPU and flash drive activity but no network activity create interference.

I tried grounding the signal and various points to the metal plate, and to move the DC/DC converter, DAC and RPi away from the amp and loudspeaker wire, but that didn't change anything.

Does anybody have any suggestion on how to reduce or eliminate the noise?

EDIT: Disconnecting the Pi but leaving the DC/DC converter on, and connecting different loads (motors, LED) to it does not produce noise.

Thanks.

I will attach the documentation for an Arduino based stepper motor control board. The starting point was to control the stepper motor originally offer by Bent Audio for a 24-position Goldpoint control, but now intended for a 47-position control. The Arduino offers the possibility to control much more than just the stepper motor, so I added 6 transistors intended to control small signal level relays. One relay is controlled by an IR mute command, and the others can be toggled through sequentially in response to a push button. With ports still left over, the last feature was to use the I2C ports to control an OLED display.

Several features are specific to my intended application. The code I developed only uses three of the input selection relays. Living in North America I wired the power transformer for 120Vac and used the space were a voltage select jumper could have been placed to add an AC port intended for the transformer that powers the rest of the audio circuits. The layout was done in KiCad and I will provide the design files if requested. As for the Arduino code, I am a hardware engineer, not a programmer. I channel my pet dog who helps me with the code, but she is on drugs for epilepsy and not always reliable. You probably should write your own code.

I have several left-over blank PCBs, and I believe a small number of the Bent Audio stepper motors are still available. More on that if there is interest.

I was wondering if anyone knew anything about this circuit board? I can’t seem to find much. It’s says Vikings Audio Forge and Bahamut project.
Thanks for looking!

A lot of doubts?

26 Driver + Ale Moglia hybrid mu-follower
-26 can drives 307A?
-26 can drives 71A?

3A5 Driver + Ale Moglia hybrid mu-follower
-3A5 can drives 307A?
-3A5 can drives 71A?

Iko DHT 3A5 headphone amp schematic:



Ale Moglia DHT 3A5 preamp schematic:



Filament Bias: a practical example with 3A5 DHT – Bartola(R) Valves

307A schade Ale Moglia info

307a DHT in triode and Schade feedback – Bartola(R) Valves

307a with schade feedback (Part II) – Bartola(R) Valves

Attached Iko 307A headphone amp output stage and Ale Moglia schade test for 307A because Ale said is the best way to use 307A but I don't know how to make the output stage with schade?

Looking for a good condition pair of Fostex R80B Attenuator.

I'm working on a Fender Sidekick Keyboard amp circa 1990, made in Taiwan. Both volume pots for Input 1 and Input 2 need to be replaced. Looks like the originals were linear taper, correct?

Hi Jan,

I really like your Mini EL84 pp circuit, can you tell me what value of feedback resisitor you settled on. I can't read your website page about it but would like to know more, can you explain the circuit in english please.

Hi,

I'll never get to building this. There was a group buy back in 2019 for it. See:

https://www.diyaudio.com/community/threads/gb-b1-nutube-pcb-with-integrated-ps.334216/

$15+$ First Class mail to CONUS.

PM me if interested.

Jim

Hello everybody.
I haven't published any posts for a while.
What better way to get back into the game?
I have a ZAPCO reference 1000.4 30th ANNIVERSARY amp that was devastated.
I proceeded to restore the power supply and 2 channels completely destroyed by a previous repair attempt made by someone else.
The amplifier turns on and works completely, but 2 channels sound less than the other 2 remaining.
The least sounding channels are the Left of both FRONT and REAR, but all channels react perfectly to all the frequency and gain adjustments I touch.
I have already contacted ZAPCO, particularly John Borges to find out if he could get a copy of the electrical schematic, but I have not received any response.
Can someone help me?
thanks a lot to everyone.

Here's a headphone amp I've been playing around with using a THAT1646 line driver in an unusual configuration to provide bias. It's fully DC-coupled and has low output offset. It's a rather long thread - I've linked in to where the schematic (as a headphone amp) develops. RMAA and FFT tests follow in later posts. People who've built it like the sound. I've posted it over at HeadWize but we can't update there right now and I thought you guys might like to have a peek at it.

Pro Audio Design Forum • View topic - Using the THAT1646 As A Transistor Pre-Driver/Headphone Amp

Wayne

Hi, i need help, help me see how much Ma is the static current of the four groups of rv7 and RV8 at the back of this Rogers ravensbourne amplifier? There are also two rv6. Is the voltage of rv6 5V? thank you,

NAD 3240PE (Integrated Amplifier) and 7240PE (additional FM Stereo Unit) - from Power Envelope Series - Pros and Cons

The fact that issues resp. failures can be observed with this amplifier more often than average - go to the wide range of threads listing in post #5 under
https://www.diyaudio.com/community/threads/nad-3240-pe-issues.333339/prompted me to find out why.

At first glance, it is noticeable that numerous parts in different areas get so hot that the circuit board is more or less colored black - go to my images from post #4 under the same URL

The main benefit of this used topology (close to Class-G) is the fact, that the peak power output is briefly so large that there is 6db more headroom available (nearly 4 times the value for power output compared to the nominal value) - check out the details in the attached PDF file, where are to find the circuit description and theory of operation in detail - so as this thread:
https://www.diyaudio.com/community/threads/nad-power-envelope.377320/

But a great disadvantage is the fact, that the front-end (LTP/folded cascode and first stage of triplet push-pull output power follower) does operate permanently on the high voltage rails (+/-70V) and not only temporarily i. e. only while the short time, where the peak power is necessary. As a result, many parts of the front end have too high idle power and thus thermal stress as to see in the above mentioned images.

Best solution from my view is the acceptance of the lack of 4–6 dB increased peak power.
To realize this in such kind, that thermal stress isn't longer present, two main steps are necessary:

A: removing the +/-70V rails (desolder bridge rectifier BD502 so as Q431, Q435 and D421 (replace by wire) for the pos. rail and
Q433, Q437 and D423 (replace by wire) for the neg. rail

B: Disconnecting the front end from the +/- 70VDC rails and connecting to the +/- 40VDC rails (R465 and R467)
On the actually necessary reduction of the resistor values for R441 (47K Uref for CCS) so as R447/449 (15K for zeners - offset adjust)
can possibly even be dispensed with (then the zeners run less hot).

check out regarding schematic drawing error in one of different service manuals around R466 from right channel post #67 under
https://www.diyaudio.com/community/...repair-nad-3240pe-advice-needed.256520/page-3

But what about the zeners D405/406 (15V) in series of the supply voltage rails for the soft clipping unit between the main input and the input of the complementary LTP ?

How works this unit, if the switch for "soft clipping" is in the "off"-position (check out the attachment in post #9) ?

R413/414 and 423/424 runs very hot independent of position from this switch.
Maybe best solution it is to remove the whole unit and replace C401/403 by a 470nF MKP.

Thank you for some advice.

The thread
https://forums.stevehoffman.tv/threads/what-does-nads-soft-clipping-actually-do.316284/don't provide the wanted information.

Hello all !

Someone can help me for give a second life to a big pioneer amplifier ?

It's a chalenge, for sure xD

I will explain the issue. I bought a Pioneer SC56 "dead" for 30euros some days ago, the first thing was to use the parts for a personnal project... But, after reflexion, I want try to solve the issue.

Concerning the amplifier :
The device start nice, all is functionnal.
The "only" problem is the sound, there is nothing on the output.
Mnaual service is the same that the SC65 : https://elektrotanya.com/pioneer_sc-65_sc-1527-k_sc-1522-k_av_receiver.pdf/download.html
No error on the display, there is no UE22 for example (because it is common to see this error when there is no sound on these old devices)...
DSP firmware version is correct (no "xxx" displayed)

I seen or tried:
Nothing is burned.
The amp is in good condition, nothing broken.
I performed many tests, and all tests was realized with a signal on the "PN/IN1" input (RCA, analog) as explained in the sm.

If I follow the analog signal, the signal enter in the "Select input" chip. After that, he goes on the preout RCA and the input of the amp modules. Simple.. But there is nothing on the Preout.
It is strange because the signal path is relatively "simple".

So I checked the DATA (VLSO) and CLOCK (VLSCK) signal on the CN3771 (This is the bridge between the main board and audio board) with my scope... I can see some packets when the amp start (it is the init of the IC), but nothing when I change the volume or change the input! So my idea is that there is a problem between the display board that send the command to the main board, or between the UPD61110 and the PE7008A (the commands sent to the Input select chip is the work of the PE7008A).
I tried to find the signal between the Display board (with the volume rotary) and the Main board on the CN7901 connector, because the two µC communicate between them by this way. I can see packets on the Pin 21, 22 and 13 on CN7901.

There is the UPD61110 µC between the µC on the display boarda dn the PE7008A.

So I resume the signal track for the volume command is :
Rotary volume -> µC display board -> CN7901 -> µC UPD61110 on the main board -> µC (?) PE7008A -> Audio bridge CN3771 -> BD3473 (audio board).

I can see the packets until the CN7901, but after, it is so hard to follow :/

Thats all... So maybe someone can help me ?

Thx a lot !

Hi everyone, i hope someone has experience with this device is an usb sound card with two jack outs and two jacks in.


what i would to know is if the jack are just connected in parallel or independent, the reason is i want the two mic inputs, its cheap so i should just test it ,but if i can avoid the waste.
I appreciate any help👍.

I have two DCX2496 and a single DEQ2496 for sale @ $400 Canadian for all three, FIRM. I will not separate and also prefer a local pickup if possible, but I will ship at the buyer's expense including any fees for shipping and handling (ie: packing materials etc). Units are a solid 8 out of ten cosmetically but are sold "AS IS" as they have not been in use for a few years and I no longer have the balanced gear to test them. They power on, seem to function fine, and worked fine when I took them out of service. Located in the Greater Toronto area of Ontario Canada. Get in on the steal of a deal!

Has anyone had a problem with the Seas Excel magnesium woofer driver! It happens to me that when I play louder.At first I thought there was a problem with the suspension so I tried to change the position of turning the driver in all directions and it didn't help.

Now it seems to me that the wire from the coil has unwound a little bit and when playing louder,and scratches the magnet.The speaker will need to be opened and repair the malfunction.Has anyone opened such a driver? If so, I would ask for any useful information about it. Thank you.!

Im going to pick up a pair of magnneplanar speakers today and from what ive been reading on Google its a bit risky without the original packaging-which the guy no longer has with them being a bit old. has anyone moved any themselves? I've got a large Subaru suv which will fit them in with the seats down but im wondering about foam-styrofoam? whats the best way do you think

I am looking at Topping PA3s.
Would it is advisable to run a 50V 5A supply to it?
And or something like this in between the power supply and amp itself?

https://www.uctronics.com/uctronics...converter-power-supply-adjustable-module.html

And/or some extra capacitor(s) before the Topping PA3s?

In music we talk about key and chromatic scales. For musicians now this has been reduced to merely going up a step.

What is a key? It opens a door. Does it do so in the music you have to listen to now?

Chromatic - the meaning of the word means . . . colour. Where is the colour from going up half a step?

The trouble is the tuning. Since the 1870s we have been robbed of doors to be unlocked by key and chromatic has lost its colour. In both, music has lost communication of emotion.

Being acutely aware of such things I'm not just interested in hifi sound reproduction but what the recording process is reproducing. So I tune pianos.

Perhaps with Login to view embedded media people might hear a difference. And I go to the extreme to test how I'm recording - Login to view embedded media and to achieve balance in conversations between instruments Login to view embedded media .

Best wishes

David P

I've had this amp for awhile. I won't bore everyone with the long story.

First what I have done.

I bought a new input board from Chris Hoppe and built it. I checked it out and everything is good. Before I installed the board in the amp the amp worked. The only thing wrong was a high THD in one channel. So the output transistors were all working fine.

After I installed the new board the right channel is perfect! I can't wait to listen to it. The left channel not so good.

Below is the output of the left channel;



Everything on the heat sink is good. I have not only checked all the transistors and resistors, most have been replaced with new ones. I only have 1 pair of output transistors installed right now.

I have done a visual inspection of the new board. Everything looks good. Comparisons to the right channel looks good, components are the same.

I checked Q107(good) and checked Q108(good). I replaced Q108 just in case it was bad and wasn't showing up on the transistor checker. No change in the output.

When I turn the bias pot R119 it doesn't change anything. I checked the resistance of R117, R118, & R119 and they are good.

It looks like the transistors are turning on too late on both sides. So I'm guessing the problem is in the bias circuit, but I'm stumped, I don't know where to look next.

Any help would be greatly appreciated!

Gary

I have a Grace tonearm which I have attached a picture of. Can anybody identify it?
sluf2

So, while Elon may need to rehearse his reveals - especially the “ one more thing” ( does Apple have a patent on that buried somewhere😀 ?), any thoughts on the impact of this prototype?
Could be some very interesting developments coming soon in battery technology that will dramatically improve cost/driving range equation, particularly on larger commercial vehicles.

Hi people,

Instead of using Ltspice I am practicing drawing loadlines to get some better understanding. I got a bit stuck with the AC load at 20000 Hz of the design attached.

The DC load must be 101.82 K.
AC load at 20000 Hz in my eyes is 2.79 K in parallel with 470K = 2.78K

Is this correct or does the 220r resistor comes into play because the signal is tapped above it?

Kind regards and thank you.

Greetings, Who made this arm? When? Any help would be GREATLY APPRECIATED!!!

Thank you, darryl

I understand jocko homo has passed... RIP.

Anyone have any ideas who could service this? I am missing it greatly as I've gone through several other converters and really want my Legato back.

Built a set of "Pensil" speakers this week. Just finished them and hooked them up to the little K-12G amp I built. So far, they are very, very good! I'm comparing them to my KEF L:S50 Metas and they are actually holding their own. The bass response out of these 6.5" full range drivers is amazing. Tight, Fast...Very well defined. The vocals are quite "Up Front", I like that....Imaging is nearly as good as the KEFs.......Efficient, the little 8w/ch amplifier drives them to louder than I would ever listen. A very easy build. Nothing complicated. Fun project...

Ohoj!

Saw this test:

PureLow LO Subwoofer | Hi-Fi+

they seem impressed but price is *steep* to say the least... Maybe some here has a cheaper recipe and even tasted the dish?

Care to share?

//

Why does this parallel quarter wave alignment cancel out every frequency after 860,(1720,2580,3440,4300…14620,…19780….end of horn resp…(-990dB)? Those are sone really unique numbers… diameter of the sun, minutes/seconds in a day…or 48,96,192 hrs… procession of the equinox, (2580) Number of days in Leap yearsidereal(14620))

location if planets, etc… This things got it all…?

if it starts canceling at 860 which is 10 cm.

that’s the basis for the speed of light previously? Per Wikipediaz . And the 8/254 version of ‘pi’’ is 3.1496. This last spike in the response is exactly 149.6hz? Following one is at Mars to 236milion km/hz /uranium before fission? And filling in the three(1/4) harmonic but not at the 5(1/4 at that same location, And then the meteor bekt in all of that? Prior to the dip right where Jupiter is 475hz…


weird stuff that goes all the way back to offset driver to El Azteca driver position found in those. Which is essentially what’s being done on both sides of this in the first segment of each.

Hi,

I have a pair of bifilar 1:1 transformers from intact audio that I used at the output of a 71a preamp.

Looks like Dave doesn’t make these anymore based on his current site.

70H 20mA.

$400pr OBO

Hi all,

After along search I have finally found something of an audio holy grail, for me at least. A Cambridge Audio CD1. As all CD afficiendos will attest this is something of a notable rarity. Being apparently the first 2 (or 3) box CD player ever made, and the only one ever to use 3 TDA1540's per channel. The sound it produces is dynamic, liquid smooth, analog in nature, with the widest sound-stage I have ever heard from a CD.

My particular example had been packaged carefully and slumbering in a box, in an attic for many years. As a result I have to say it is in almost new condition. I had been using it for a week or two without fault, but have now noticed a grumbling gear noise when the CD drawer is opened and shut (occasionally needing a helping finger to finally close).

Not wanting to cause any damage I have decided to stop using it while I sort out the problem. The drive is a straight lift from the early Phillps players, that is the CDM1. As most will know this is a long lasting unit and mine shows no problems tracking and reading disks.

I have replaced CDM1 mk2's, CDM2 mk10's and other drives in older machines with direct replacements, so I'm not a complete noob in this. As many know though the drawer mechanism on the CDM1 machines are quite complex and before I strip it down, I would welcome some or any advice on what the gear noise issue may be, so that I can be forewarned.

I have attached a short video which hopefully shows the problem.

Thanks and best wishes to all.

Found a couple of PCB's for an AlephJ. Asking 10 euro each.

Also would have parts for them as well like 2SJ109 and selected IRFP240's

new in box, $125 each plus shipping. Also have 3 nc400 amp modules, new in box, for $300 each. Will discount if all items are purchased.

$1000 for everything. Buyer pays shipping. Thanks.

Well, I've wasted hundreds of £££ paying for 'protection' on parcels over the last years with parcel2go.com

Their cover does not include speakers or amplifiers.

I'm not saying don't use them. ALL couriers and agents try to get out of paying for damage. Just don't waste your money on protection.

I'm glad they highlighted this when I entered the item description as 'loudspeaker' or 'amplifier'. NOT!

Hi All,

I posted earlier that I have readable schematic for this NAD 3240PE. I am happy to share that, if anyone want a copy.

Now I have to try to solve the problem - the right channel doesn't respond to the balance adjustment as it should.

The amp sounds very nice, completely noise free when nothing is playing. IF I turn the balance knob all the way to the right and then just a little left to get some left channel going I can turn it up and get very pretty sound, but the right channel has only a tiny fraction of the left channel power.

If I take the Pre Out to another amp it sounds just fine, but when I use the integrated amp not much right channel.

I am surprised by this, I would have expected the balance pot to be a preamp failure, not manifested by the power amp alone.

I tried the usual contact cleaner hose out and rotate business. No difference.

I am attaching images of the schematic (the rest of the service manual has component lists, wiring diagrams, etc.) that can be placed side by side.

I probably just don't understand how the switches and pots work together and all I need is a new balance pot, but I could use any trouble shooting advice you all are willing to share. Should I go for a volume pot, too - while I am in it?

Thanks! BentMike

Hi all,

I recently bought a 300w sub with a broken power board for 15 quid.

I stripped out the power board and the fancy low pass filter, frequency modulator, and volume control board out. Then bought an L7 MOSFET mono power board that supports 300-350 W at 8 ohms as well as requiring 2x 50 V in, this is exactly what the transformer outputs and what the driver requires.

I also picked up a 2M ohm potentiometer for volume control and a 100Hz or so highpass/lowpass filter (i always get it the wrong way round)

because it's a mono out board I'm having a lot of trouble trying to work out how to correctly wire it all?

Any help?

Finlay.




(https://www.ebay.co.uk/itm/221254643945?_trkparms=amclksrc=ITM&aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=20200818143230&meid=f1091f7470794e6eb76178fa92c156f5&pid=101224&rk=2&rkt=5&sd=224405663394&itm=221254643945&pmt=1&noa=1&pg=2047675&algv=DefaultOrganicWeb&_trksid=p2047675.c101224.m-1 link for power board)
(https://www.hifigear.co.uk/epos-els-subwoofer.html link to sub)

I've read a bit about capacitor microphonics being a problem and have read that some have zip tied caps to the board or used hot glue. About ten years ago, when I built my first outboard, I put the caps on thin sheet rubber and secured them tightly to the board with zip ties. But now I wonder if the vibrations causing microphonics are within the capacitor and securing them to the board doesn't eliminate the problem. Is that the real problem or are zip ties/hot glue the cure?

Credit to Mark Johnson's design

4 used stuffed boards in great working condition @ $9 per board + shipping & paypal fee in continental US. They're stuffed with 50v caps.
10 bare boards @ $2 per board + shipping & paypal fee in continental US.

EDIT - ALL ARE SOLD. THANK YOU!

Note that the bare boards have mounting hole and are thicker ones. If you decide to pay like gifts then there is no fee. They're small and I'll use first class mail. Don't know how much it costs to ship, figure 4 - 5? If it costs less to ship I'll refund the difference.

Thanks for looking.

Duc

Greetings to everyone!
Own this C.E.C. TL51XR cd player is about 2 years and now I decided to make major changes! I was inspired by this for upgrade digital modules: cectl51x

I started with the power module. Here I replaced all regulators with Newclassd UWB DX78XX/79XX regulators.
Photos before changes.

Hello, wondering if anybody knows where I can purchase an amplifier that has the same sound signature as my pm860

I have owned and repaired quite a few of the little Soundcraftsmen PCR-800 & PM 860, pro power series etc amps and found them to be excellent performers.
Even Audio mag reviewed them highley, slightly better then the Adcom 555 amps.

Has anyone else played with these and done any mods?

How about the PCR, Phase Controlled Regulation power supplies? i have never seen another company use such a design? (maybe for a reason?) any thoughts on the PCR design??

I have done some simple mods like upgraded the PSU caps and added bypass caps, cleaned up the internal wiring and upgraded jacks etc.

These ******s can be had really cheap and they sound pretty good. My Bryston 4B had better bottom end, but these seem a but less harsh on the top end.


Zero 😎

Hello,

building two pre-amps using this http://www.tentlabs.com/Products/page31/page31.html

As far as I understand it, it does have a self-power off function )perhaps if no signal detected for some time? Can anyone confirm as Guido`s not answering my emails (hope everything is allright with him)?

hi all im starting this thread in the hope its as popular as the beringer thread and to give everyone who has any of the dbx driverack units a place t5o discuss everything about them including setup,modifications and others .ive personaly got a new driverack 260 that is going to biamp my new speakers which are 2way with eaton 12" hexacones for bass and manger transducers for the mid and highs .im using 2x goldpoint attentuaters for volume control in between the dbx and the hypex ucd400 hg modules which have the superregs fitted .once setup id like to do some mods on the dbx to see how good it can sound .ive got some ideas which are to add an outboard powersupply ,some cap upgrades and maybe play around with the opamps and clock .im hoping all the other dbx users will chime in with their thoughts and suggestions

I just picked up four of the russian 6N7S tubes with the aspiration of puttng together some type of class A (AB-leaning-heavily-A at least) push-pull amp. I chose 6N7S's because they are readily available and they put out a decent amount of power. I was a bit surprised to see that they've been traditionally used for pure class B, but I hope they have some real hi-fi potential.

If each bottle has a 12W max dissipation, I'd dissipate around 20W per pair, hoping for around 10W of nice audio. Is this feasible? I don't have a printer so I haven't done any load line drawing, but let me make sure: with the PPP setup, the load impedance that EACH triode sees is the same as the anode to anode impedance of the OPT right? Any ideas about what OPT primary impedances might be best for such a project?

I'd have to look at some load-lines to see how much swing is needed to drive the tubes but I have a few 5687's kicking around that hopefully could be up to the task. Maybe an LTP feeding a regular grounded-cathode stage? a LTP'ed SRPP?

If such an amp isn't practical I'll just save these to use as somewhat beefy drivers for another future amp. Planning ahead, I am 🙂

Does anyone have any Avid Turntable repair info??? I just repaired a Volvere and I need to know the value and speed rating (fast or slo blow) for the 2 fuses inside the power supply/speed controller unit. I have reached out to avid several times with no response so far.

Hi, looking for a valve amp, can be as low as 4watts for my kirishima speakers, more than 95db
Up to £2k
Ideally single ended.
Thanks.
Graham.

Recently i made a gainclone based amplifier & faced a weird phenomena. For test purpose i was using a simple opamp gain stage(6dB) to boost the output signal of a Bluetooth mp3 player. For preamp & mp3 player i used 7xxx based regulated power supply. Anyway when i was turning off the whole thing there was a terrible loud thump /squealing after 1-2 second. I tried different opamps (5532/072/353) but result was the same. I checked almost everything but i failed to get any clue. The mp3 player was connected to the positive rail of the preamp, to find the problem when i disconnect its supply(5v) everything becomes normal, no turn off squealing. Then i realised it was happening because positive rail collapsing faster then the negative rail & it turned out to be true! I added a LED load to the negative supply rail & voila! No turn off squealing now 🙂

I thought i should share this with everyone. Anyway have a nice day folks!