I have four 4 ohm, 40 mm drivers I wish to use to make two vented enclosures for 200 Hz up (flat above 200, hopefully). Each enclosure would have 2 drivers plus a tweeter.

However, these four drivers are two separate pairs, and they're slightly distinct, one pair having higher Fs and lower Vas than the other, but the rest of the parameters (like Xmax, DC resistance etc) being much more similar.

I already have an amplifier to use with them, but it can only use loads down to 4 ohm (at least in principle). So I should wire them in series.

And, if I want the left and right side enclosures to sound the same, I should, in principle, use one of each pair in each side, so each side would have 2 dissimilar drivers.

But coming to think about it, I think this would probably not be a good idea either.

To begin with, even if I made a separate cavity with its own vent for each driver, the fact they're in series is still a complication. They have different impedance curves, and I can't simulate each driver as if it were in series with a simple resistance, it's in series with another driver, that's not mechanically coupled to it anyhow.

And WinISD at least can't simulate that.

I thought for one second about measuring the TS parameters of them in series like they were a single driver, until I realized this would only make sense if their cones were also mechanically tied together, always moving as a single thing.

Maybe, then I should make each side using one pair, and just try and tune them to be the most similar as possible? Their phase response isn't going to be the same though.

Plus, a small question: Do you know if, when using more than 1 driver in a WinSD project, it considers they're in series or parallel? There isn't an option for that, that "voice coil connection" option is for drivers with a segmented voice coil, not for the connection between the drivers. I'd assume it considers they're in parallel.

If it considers they're in parallel, it's a further complication, as, in the case of using one pair in each side, I'd still like to wire them in series.

What would be the best way to go about this?

Thanks!

I've been taking a look at an alternative approach to RIAA equalisation that has been patented in the last few years (https://patents.google.com/patent/US20170126186A1/en) by Graham Slee. This basically equalises the pickup's constant velocity frequency response by putting an integrator as the first stage providing the 3180us pole (50Hz). This effectively provides a constant loop gain for that stage. The remaining 318us (500Hz) and 75us (2122Hz) time constants can easily be dealt with by a simple passive filter. My take of an MM phono using this approach is attached. I've include a secondary LP filter to address the non-inverting amp's roll-off at unity gain, a 20 Hz rumble filter and a simple flat gain stage with potential gain adjustments to allow for differing cartridge output levels. Overload margin is in excess of 30dB for a 5mV MM cartridge.

I've modelled the input stage with an OPA1656, a very low current noise/low distortion FET op-amp. Other suitable choices would be OPA1641 / OPA1642 or similar. As an aside, the use of a FET device as the input stage will also provide good RFI proofing.

This has been built and is my current phono amp in use on a regular basis. On a subjective basis, its clean, precise and provides an open sound stage. As far as measurements go, I've run a quick and dirty frequency response check using an HP3312A function generator, inverse-RIAA network and an analogue 'scope. This confirms the flat response across the 20Hz to 20KHz range. I also confirmed the overload margin.

Hi All,

Does anyony have any experience with this input module?
Good idea/bad idea? an alternative?any suggestions about it?

TDA1540 Module


I have a CD player with TDA1540 Dac chips and would like to "convert" it to a Dac only.

Thanks

My mtx7801 amp was running and voltage dropped below 10v
Amp stopped working. No power lights, no protection circut light, took amp apart and hooked up power and led 401 service light is blinking, no obvious part failure on board, where do i start testing.
I believe amp was repaired in past, cannot upload puc files are too big. Guessing its a fet attached to heatsink. Will link thread with pic that matches mine, explenation of whats going on?

Hello guys I repairing my HP3632a power supply and need to find a replacement thyristor for CR28 on the schematic, it's a MCR264-4 , closest I can find on Digikey is a S4040RQ3TP .. I am quite new to the electronics hobby and have done quite well finding replacement transistors but some are a little more challenging and I could really use some help with this .. The problem I'm finding is knowing how far I can deviate from spec on a transistor ..

Recapping my dynaco 120. Amp board calls for 250 uf / 50v caps. Hard to find can I use 220 uf?

I am selling an Onkyo model T-4310R FM stereo/AM tuner used but in great condition, as you can see in the pictures below. Fully functional, no scratches or dents. I have both user and service manuals in digital format.
Asking US$80 paid via Zelle. I am willing to ship if buyer pays for the cost of both packaging and carrier. Alternatively buyer can pick it up in Huntington Beach, CA and pay cash.

Has anyone used spray paint on wood with the intention of keeping the grain visible?
What problems did you run into?

I am making bases for gem stone cutting machines so this is not furniture. When I got the contract was a simple stain and poly job.
Now the color scheme of the machine is being updated from to black on black. Black stain looks washed out and is hard for me to keep from being blotchy across the several applications to get a deep color. I can add pigment to the stain but in my mind I am just adding solids to the oil based stain, you know, i'm making paint that is a hassle to apply.

Why not just skip the hassle and use spray enamel?

I'm looking for critique . Why might this be a bad idea?

Jeremy

Meter light is out on my X250.8 amp.The stand by works but meter light is out.Any suggestions on a fix?

Thanks

The standby light is on but the meter light is out on my Pass labs X250.8 amp.The amp works fine except for the meter light is out.Any suggestions to repair this?
Thanks

SOLD

I picked up this pair of HF108R about a month ago to measure and test with a couple different horns. Have about an hour of use and are essentially new. Sounded great. Paid $442 via Parts Express.

Asking $330 USD via PayPal F/F (or add the 3%) + actual shipping cost

My speakers are three-way system and the stickers at speaker terminals are labeled 8 Ohms nominal. However, I have measured the drivers’ resistances (Re) by a RLC meter and they’re shown as follows:

Tweeter = 3.2 Ohms
Midrange = 3.4 Ohms
Woofer = 3.6 Ohms.

IMO, these all should be 4-Ohm drivers.

So, why the manufacturer claimed they’re 8 Ohms nominal?

I know the speakers have an impedance curve which could be fluctuated depends on frequency. But the 8 Ohms nominal is the result of averaging with the peaks on the impedance curve, isn’t it?

Does anyone have experience with this Sanken Power Amplifier Module?

The only "name" I can find for it is "DX-45M" on the outside of the box.

I don't seem to find anything with a search for "diyaudio DX-45M" so hopefully it is ok to start a new thread.



I would like to try an amplifier with Sanken outputs to see how it compares to the K1047 based amplifiers I have tried. (MX50X2 & L20.5) After the comparison I might order some of the still available MT100 smaller Sanken devices from Digikey to try in my other projects.

It is described as "SanKen 1494/3858 High Power HIFI Audio Amplifier Board Dual Channel 450W+450W Stereo Amp Mono 800W Amplifier Board For Sound DIY"




It is attractive for me for a quicker project since the heatsink, power filters and speaker protection are all integrated.

If you have this amplifier please let me know what you think of it and if you would recommend I try it. Also if you have it do you have a schematic? Any idea of the internal amplifier structure/type? Such as Blameless or something else?




Also, has anyone more extensively tested and evaluated clone SanKen 1494/3858 devices? I ask since I would not be surprised if this came with clone devices. It is also why I would like to find someone who owns this amplifier and can offer their first hand experience.

I have an almost new SONY TA-F444ESII with ATTENUATOR issues.
In the times of old we would just rotate a few times to wipe it clean, however this sorta helps.
Even after the wiping one channel or both are either static or not there, a few more wiggles and things settle down.
Most times it will play all day with no issues.
Does anyone have a fix for this? I bought this guy in 1985 and have enjoyed it a lot.
Looking online has produced no parts or links this site was great to read for some other issues and how to check/correct.
I live in Southern Georgia and know of NO shop to contact. All help is appreciated
(And almost new is relative)
Thank You
wmildman

Does anyone know what the specified slew rate of the TDA2040 is supposed to be? I haven't found it in any datasheet, or anywhere else at the internet yet. The reason I wonder is because I just measured the slew rate of my old TDA2040 amp, and was just around 4 V/µs (!). No wonder it sounds worse compared to my other amps.

Could this really be right? 4 V/µs is a really low for a 25 W amp. I built the amp as suggested by the datasheet with a dual supply of +/-16V. One of my first projects as a teenager and thought it sounded ok then...

Trying to repair a Crown Grounded Bridge 460CSL. This is a cut down/ cheaper variant of the Micro-Tech and Macro-tech. The Dim bulb is full brightness. Traced to one channel on high side.

Removed drivers and output devices on high side, switch on and short clears. All devices measure fine/no shorts. Installed with known good devices, Crown graded outputs and Sanken drivers from my spares, switch on and dim bulb full brightness. Removed drivers and dim bulb is dim!

Removed ribbon cable to high side and short clears!

Tried with a known good main module and the exact symptoms appear.

Removed op-amp from board and no short!

I'm at a total lost to why this happens.

Schematic is the Geodyne version (similar)

Built several speakers over the years, but need some help with my SP10.

I picked up a Pass Labs X1 pre-amplifier and it has a 12 VDC "Amp Turn On" output signal. The manual specifies it handles 50mA max. Has anyone found a way to use this signal to turn on/off the external amplifiers that don't have this feature? I was thinking to insert a relay to close the power switch in the amps when activated. Alternatively, I could avoid modifying the amps and build switched outlets. I have two questions to ask:

1. Is doing this a bad idea?
2. What relays and/or circuit should I use?
   The relays I found either don't provide any current specifications on the DC input at all or their rating is too high (~48mA per relay).

Thanks.

Long time diy builder first post on this forum. 😊

Excellent condition, bought it old new stock from Fritz of Fritz Speakers. He used them in Carbon 7s speakers. One spare driver is left and is for sale. I know that 18W/8545 retail for $240 each or more if you order then in Europe with shipping they are $300 each.

See the pictures it is in excellent condition, it was stored properly (cone down). You can see resistance measurements on my multimeter.

$75 shipped in cont. USA

For few years I have Alpine SWR-1542D. On paper it looks nice but so far I am not impressed.
I have it in my car and have it paired with Hertz ML Power 1 amp. 1542D has RMS 750W and I was pushing 1000W with the amp, no problems.

As it's a 15" sub, it's a bit on the bigger side but I wanted a sealed enclosure anyway as it's simple to make and I wanted to focus more on SQ. I made a sealed enclosure recommended by the Alpines manual. Which was ~46L net volume. Big mistake as it is underwhelming.

This is what I built:



Odd shape shouldn't be a problem?
Anyway with Qtc at 0.806 it should have fsc at 43 Hz. And this is what the transfer function magnitude looks like with 18 Hz 24 dB/Oct highpass filter and 120hz 24 dB/Oct lowpass:


Blue is Alpine recommended 46L sealed enclosure and red is WinISD recommended enclosure around 73L, fsc 37 Hz, Qtc 0.707. F3 at 40 Hz.
If highpass and lowpass filters are working as they should then this should give pretty good idea how it's going to perform?

Now I want to make a bigger enclosure and I feel like I want to try 6th order bandpass enclosure with a "neat" trick of making front and back chambers separateble so I can remove front chamber by unbolting it and using back chamber as smaller vented enclosure if needed. Might be dumb idea?

I am also wondering if perhaps my amp is limiting performance of my sub with the highpass filter always on? Especially for the sealed enclosure? With it on, according to WinISD my cone excursion can barely do over half, around 12-14mm of its Xmax which is 20.5mm.

Whether going with vented enclosure or 6th order bandpass, I have roughly available gross volume 208 - 228L, around half of my trunk space. Should be big enough.

I have calculated using WinISD that 108L vented box tuned to 28Hz would give me transfer function magnitude ( Green ):

This is probably too peaky. Should I try to flatten it out?

108L tuned to 24Hz ( Orange ):


Here are my SWR-1542D T/S parameters:


I need to fiddle around more in WinISD and see if I can set up 6th order bandpass so it gives a decent flat response with good enough low end. But that's for another day. Meanwhile I don't mind to get some tips and tricks to help me figure out a suitable setup.

Regards,
Karl

If using REW in Rta mode with averages set to ‘forever’ can we get a pretty legit look at cabin resonances/room modes quickly? So far I’ve just been analyzing music for freq content in this way …

I like amplifiers and tube amplifiers because I enjoy listening to vocals, slow melodies, and I also like listening to cassette tapes and vinyl records. I have loved listening to music since middle school, and it has been 20 years now

I've been looking around for an board, something like the CDB4272 or a circuit board that I can have made at JLCPCB or others, that would have two channels of balanced analog input with AESBU output, ideally, or I2S/SPDIF.

I have a lot of old recording equipment like DAT and ADAT that I like to use, but their ADCs are 30yrs old. I have a couple outboard ADCs but they are over 10yrs old too. I had thought about using the CDB4272 but that eval board is like $450 and I could probably draw the schematic and have my own made. I'm very good with micros of all types, have tons (literally) of test equipment so making a debugging isn't a big deal, just wondering if anyone already went this route and has a board posted someplace? Output needs to have 16bit at 48khz minimum and then selectable higher bit and sample rates. I also need the word clock output.

Thanks

Jerry

Hi,

I have developed a freeware program called HOLMImpulse for speaker gain and phase response measurement.

HOLMImpulse is Non-Commercial freeware with full functionality (No limitations or trial periods) running on Windows XP/Vista

Download HOLMImpulse here

The purpose of the application is to:
- Work with any soundcard
- Easy and fast to use
- Measure Frequency-response (gain and Phase)
- Measure Impulse-response
- Dynamically/Automaticly adjust the time window (Gating)
- Use cross-correlation techniques with logsweep, chirp or MLS
- Very good signal/noise ratio (Due to cross-correlation)
- Make bandwitdh limited measurements with no phase-errors
- Measure Harmonic distortion (THD)
- Compare measurements (50 slots, and 3 shown at a time)
- Easy open/save import/export measurements in any format
- Be freeware with full functionality (Up to 192KHz, 24 bit)
- Manipulate measurements (Lowpass, highpass, etc...)

I would like your response
I know that there is no manual, but we are all geeks who rather want features than manuals - right?
- Simply define select your soundcard and click measure
- I would like you to reply in this post and tell me if you have had any success with the program
- And of course post your measurements ;-)
- If you have any difficulties getting this to work, then I'll assist you in this thread

NB I am working for
HOLM Acoustics (A new small Danish Company),
but I have no commercial interest in HOLMImpulse, which is mostly developed in my spare time. The core libraries used in HOLMImpulse are the same as in
HOLMFIR, which is a program used to configure the commercial product DSPre

I have a powered sub to go with my HT 5.1 system. I also have a small 6LU8 tube amp for my turntable and streaming. I also have two sets of speakers, both are 89db sensitivity, so the 3 watt or so amp needs a little low frequency help.

Anyway, the HT amp is hooked up to the sub with the amps sub out. Since the tube amp does not have a sub out, I would need to use the speaker level inputs on the sub. My question is this, will connecting both of these inputs work? I typically use only one amp at a time.

Roger

Hi Everyone
I've had a Technics SLP-310 CD player for many, many years which my wife bought me when CD's were a novelty. The unit works perfectly once I have left the power on for a few hours before use! When switching on, the laser seems to scan the disc but doesn't indicate how many tracks and the disc duration after the initial boot up. When I leave the unit with the power switched on for a few hours and then return to put the disc in the drive it reads and plays perfectly.
Can anyone explain what may cause this and also if there is a solution to rectify the problem. I've cleaned the laser lens and had capacitors replaced by an audio engineer but he is at a loss regarding the cause.
Obviously, the laser head works otherwise there would be no sound after the extended warm up scenario.
The sound quality is superb through my Quad 33/303 and Spendor BC1 system and the unit has a sentimental value as well so I am loathe to purchase another CD player.
Any help and advice anyone can offer would be most welcome.
Thanks in anticipation.
Chris

Hi,
I want to draw higher current by increasing the number of output transistors (2n3772) in the schematic. How can I do this. I also want to use 2n3771 in this revision.

Hello,

Does anybody have experience driving very low resistance speakers? AP333 BL field coil driver has fallen into my hands, I expect that I will need max 1.5 W max to drive it. Is there standard OPT’s available or this can only be custom wound? Driver tube I have not decided yet, but it would be interesting to use something like D3A in a SPUD configuration..

The thought crossed my mind on building the Elektor 'Crescendo millenium' amplifier.
Quick look at the output stage shows 2SK1530 and 2SJ201.
Those parts are obsolete and I haven't found any parts that could serve as replacement.
So my question is if someone recently acquired a pair of them and where and were they the original.

Hi all,

Searched for existing posts on the subject but couldn't find any so here goes, anybody here with experience boosting the 3116 max output current using external hbridged mosfets to allow 1 ohm loads ?

Am using 4 4ohm drivers and would like to parallel them.

Never thought I’d even think of selling these end game speakers but here we are .

Built by Jason of Arke Audio with no expense spared and then the crossovers had an over £500 worth of component upgrades.
There is plenty of information about these these actual speakers over the internet.

These do like a powerful amp to get their best , I was driving them with my Threshold Stasis II which I may also list once these are sold .

I’m unable to offer shipping on these for obvious reasons.
They are in Buckinghamshire UK
£3500 no offers please.

Hello, I have always powered my trusty analogue scope via an isolating transformer to avoid grounding one side of a floating power supply (for example) when measuring. Do people do the same for their DSO's? Model in question is the Hantek DSO2C10.

Hello all i received the new kit for the mx50 finished building it it ran for about 30 sec and the the gray 10ohm resistor burned. Any ideas why this would happen it looks like it’s on the out going to ground with a film capacitor I believe the value of the cap is 100nf . I’m really bummed I just turned them on and both same thing happened music was playing and then boom smoke from the gray cap everything else on the board looks fine !

Hi guys !

I'm looking for a service manual with schematic for Yamaha TF3 digital mixing console, especially for the HACOM HAAD input board.
I have a desk, and on channel 23 below 17db gain the signal is almost lost, but when the relay switches it's all good.

Hi, I’m owner of Myryad MXI 2080 Integrated Amplifier. On Sunday 24.07.2022 we had a rainy night with lighting strikes, in that moment the amplifier was turned on and something happened, the circuit breaker of the socket where the amplifier was connected went off. I turned it back on, all equipment that was connected to this socket turnes on, the amplifier was in standby mode, when i tried to turn it on, the circuit breaker goes off again. I disconnected everything, but the problem still persists. I started the troubleshooting:

1. I have checked all the fuses — all OK , no black spots on PCB’s or black components.
2. disconnected the power connectors on amplifier channels PCB, the same result.
3. disconnected the supply of toroidal transformer and the amplifier starts in normal mode.
4. checked the resistance of the primary (input 230V) it shows 3K, checked the resistance of the 2 x output 1.5 Ohm.
   Something happened with the power toroidal transformer.

The model of this transformer is:
TI-043316 AU Iss 2
Part No: OT2300021 230/120V
Thermal Switch 120 Deg SL0547

I wrote an email to Myryad but still any answer. That's why I need your help, does anyone have a service manual? maybe you can recommend me an equivalent transformer, or a datasheet of the main this transformer?
Please help me to solve this problem.
Thank you!

Hello, i have 2 “500w” more like 250w irs2092s boards, connected to a dual +-75v supply
At the moment, one board connected to a single coil subwoofer runs just fine.
I was wandering if its possible to have 2 irs2092s board connected to a dual coil subwoofer (1 amp to each coil)
Would anyone knowledgeable about the irs2092 know if i could daisychain the two boards (wire in parallel) to one dual voltage supply and have the output of either board go to either coil, without damaging the boards
Welcome to provide any info.

Edit: the max 1.5v audio inputs of the boards would also be daisy chained together, because of course giving each amp different signals would either break the amps or the dual coil sub

8NTLS2000 looks like a great driver anyone tried. How would you use it best

For sale: NOS original Harris 9623 datecode IRFP254

These have good SOA and nice linear transfer characteristics.

Transistor, N CH Mosfet. Max voltage: 250V. Max current: 15Amp. Dissipation: 190 Watt. Package: TO-247AC. P/N: IRFP254. Note: RDS on: 0.14 Ohm

Approx 30 available.

Asking €3 each.

Shipping Worldwide at cost.

Hi! I am Currently using Gustard A26 DAC. Recently I bought Gustard N18 network switch. After a month of using decided to upgrade the caps. Power Supply caps were Nichicon FW 3300uf 25V and some 220V 25V caps again FW. Decided to try out upgrading the caps. I bought some Nichicon KW and FG from Mouser of the same value replaced those. I immediately noticed difference in sound compared to Nichicon FW. This got me thinking to looking in Gustard A26 Analog section which again used all Nichicon KW caps.
Will Upgrading to Nichicon FG make difference to the sound? And what can be expected when compared KW with FG / Silmic II / Audio Note Kaisei.

Thank you.

Hello DiyAudio

Hello all, My name is Ryan from Indonesia. I'm really into Loudspeaker world. Hoping for guidance in this forum.

And sorry for my bad english because it is not my primary language 🙂

The Boston Audio Society (BAS) is looking for someone whould would be willing - against payment - to write up recorded meetings for the BASSpeaker joutrnal.
Also for someone willing to help maontaining and updaing their HTML website.
Let me know if you are in principle interested and I will send you a journal sample and hook you up.

https://www.bostonaudiosociety.org/

Jan

I have used the same RCA cables forever and never cared much about cables before until now.
I needed to rearrange the system and I was in need of new interconnects and so I bought some Mogami cable (maybe the gold version?) and some nice Neutrik plugs and made a few cables. The difference is very obvious, the HF/MF detail is much better. I wonder what people are using around here as interconnects. Particularly in the home made range. Has anyone compared the Mogami cable with other brands?
thanks!

PCB Kits for the Richard Marsh Headphone amplifier, these are the improved boards of RM Marsh original schematic, designed by Prasi.
They can use multiple types of output transistors. Kits have matched Toshiba 2SA1930 & 2SC5171 and sound superb.

Kits include two Marsh HPA boards, one Golden Reference PSU and matched set of Toshiba BJTs. - £20 plus shipping



Also selling HiFiSonix (Bonsai) SMD HPA with golden reference PCB plus two Extruded heatsinks, I will include a set of matched Toshiba transistors. - £15

To our members from India, please enlighten us on Ebi Audio.

https://www.ebi-audio.com

https://audioxpress.com/article/r-d-stories-the-neurochrome-story



dave

A friend had a Marantz 240 where the speaker protection relay would never engage. Discovered it had some bad transistors on the right channel. Replaced them and the idle output voltage differential went to ~0 Vdc. Relay functions as expected now. Thought I was done.

However, the left channel exhibits clipping at around 4.5 Vdc. None of the transistors seems bad or even particularly weak. There were a few transistors that tested strong and worked after reflowing the solder, and others with no obvious issue.

Someone was in this thing long before me, and there are a few non-standard parts on the relay board.

The signal looks clean until it gets to the point where the signal and feedback mix after the diff amp, and I'm not sure how to suss out what is clipping distortion in the feedback and what is distortion in the desired signal.

Waveforms taken at speaker output across 8 ohm resistive load.

Any ideas?

Hi everyone, perhaps this idea has already been discussed. Here it is : As most of the energy of musical programs lies in the lower frequencies and is from almost to completely mono (as you can experiment if your speakers are reverse connected), a great improvement in power amplifiers PSU needs would be to invert the phase of one of the stereo channels (and reverse one of the speakers connection to restore the acoustic phase of course). As you can see on the shots (music program, phase / anti phase, same scale), the instant need for current is dramatically lowered in the "inverted" configuration. Channel blend, PSU regulation needs and instant symmetry of the current pulses in the transformer are improved as well. For stereo class A amplification, mono signals result in zero AC current. Plus for single ended amps : distorsion of mono signals is improved as the acoustic sum of the signals means anti-phase amplification as it is done in push-pull amps, where the sum of the signals is magnetically done in the output trans). Inverting the phase of one channel may be very easy (for instance for phono preamps, just invert the connection of one of the coils of the cartridge). Digital sources can be modified in the digital domain, analog sources will need an inverter. Not an issue anyway : transformers, tubes, transistors or opamps can do the job.
Could deserve a try as it is an easy mod.

M.

Stereophile magazine has gone through some changes. Art Dudley passed. John Atkinson stepped out of the role of editor as Jim Austin stepped in. So when the newest issue (September 2024) arrived today, I wondered what they would say about the Pass Laboratories XP-27 phono preamplifier.
John Atkinson did the tech review and he is a long-time appreciator of the work of Wayne and Nelson. The usual mix of tech & modesty is present in the review.
--------------------

“The rectifiers are upgraded, Colburn said, “and have suppression to stop ringing and to lower EMI.” Nelson was slight more specific, noting the addition of “separate snubbed rectifier bridges for each polarity.” Nelson also mentioned CRC filters: “All this to lower noise,” both over-the-air RF and on the AC line.

Click to expand...

(Editor Jim Austin) noticed that, despite all these changes, the noise specification is unchanged — the same as for the XP-25. (He) asked Colburn about this. “The noise differences don’t show up in the specs because they are out of the Audio Precision analyzer’s measurement range,” he responded. “I measure on a stand-alone spectrum analyzer. Having had my hearing tested, it also falls out of my ear’s range. Why it seems quieter, I don’t know.”>
...
In the conclusion, Austin said, “With the XP-27 in the system, specific musicians were easy to identify, and the character of each of the three phono cartridges I used was instantly recognizable.” Of course they love the XP-27. Congrats to all.

New member just got approved, thanks. Old guy audio nut 50 years. Working on my Empire 598 Troubador Mk III.

Aleph Bet is a single stage, single ended, unity gain, line level buffer that can drive a 2kOhm load with vanishingly low distortion.

It uses a composite transistor known as the Baxandall Super Pair (see the attached 1966 article) in the follower role with an Aleph current source (as described in the attached patent by @Nelson Pass) as its load, hence the name. A few twists have been added to that general theme and can be glanced from the simplified schematic:


The distortion performance is quite good (note that this buffer has distortion well below that of the ADC, so the fundamental is suppressed after the buffer and before the ADC in order for the ADC not to add its own distortion; the actual signal level buffer is working with is 6Vpp):


These measurements were taken with +/-15V power supply, 2kOhm load, 6Vpp (=0dB) test signal, which was suppressed before the distortion products were measured.

Aleph Bet is a development of the original idea proposed by @Lenin from the RCL-electro.ru forum.

Details will follow shortly.

for the needs of a small setup I use 2 tham 15 and 2 rcf tt22a driven by 2 channels of a lab c48.4
the 750w satellites have 131 db declared, while the bass ones are the tham 15 with faital 15hp1060 driven with 1000w they should have 130db
To avoid bringing 4 subs, I would like to achieve better bass performance using the speakers I have, I don't know if it's a feeling due to the fact that more bass extension would be needed or I need more db in the same range.
However, I would like to do a new project also because I have the doubt that at high volumes the wood used, 20 mm conifer phenolic plywood, perhaps has losses, given that everyone finds the output of these subs monstrous.

what do you think of the various paraflex C, O that would be suitable for my woofers?
or the ss15?
the roar 15 is an old piano, it seems like a cross between paraflex and TH.

or should I change the type of upload, such as bandpass etc?

I have other unused woofers available: 15hp1030 which are the ferrite version of the 1060, 15nbx100 from b&c, and I also have 2 18 faital 18hp1010 - 4 ohm, they don't have an exaggerated bl, but I could see using them in a tham 18, the final would give 1200w/4ohm.. what do you think?

I could, in this case, make better use of the power by putting the power amplifier on 2 bridged channels and limiting the output 🙂 it would become 2400x2 /8ohm
thank you 😉

Hello. I have a problem with the heybrook HB1 speakers. After connecting them to the amplifier, the tweeter does not sound, but hums. I pulled out the crossovers and checked under 1.5v and reacted. Then I replaced the capacitor with another one and only at 470uf it started to play nicely. On the other hand, when playing one of the PR speakers, touching the screws that fasten the speakers means making some crackling noises. Ground loop?
16 wrze?nia 2020 - YouTube

Brand new in original boxes 15" woofers, look, I know that you always wanted to build a 15" system but kept putting it off, here is a great chance to pull the trigger and save money, it's a win, win.

195+ shipping

Sale Closed.

Thanks for taking time to read this listing.

If you buy from facebook marketplace make sure you can go along see the item and pay for iythere.

Just got scammed.
I bought an item and paid via paypal straight away with given email address.
After a few days seller asked if I still wanted it.
I said yes its paid for.
Seller came back and said I had paid wrong email account.

So onto paypal to make a claim.
Person with wrong email address said he had a receipt for the item with my name and address on it.

It looks 2 or 1 people in cahoots pulling a scam.
Will just have to see what paypal do.

Hi there,
New member from Pennsylvania. Been an audio DIYer for over 50 years. Not sure why I never joined this community before. One of my memorable audio experiences was listening to a pair of Hill Plasmatronic speakers which used helium fueled tweeters. My girlfriend at the time went with me to a listening event. As of now we have been married almost 45 years.

Hi all. Here my last group of vfets. These were selected for my personal use, but I need sell them for getting cash.
Here I offer: four 2sj28, two 2sk82 and 8 2sk79.
The 2sk82 were measured a long time ago with my own version of circuit of MR and curves were very good. Attached are curves for 2sk82.
These matches very good with marked as 11 and 22 of 2sj28. I have not curves for these, but I used the test circuit, searching Vgs for 1A with 19V (22 Vgs=6.98V and 11 Vgs=6.63V)
These are very good for CSX1 circuit. I built this wonderful amp. Wow....
The Vgs for the other 2sj28 are... 19 Vgs=6.28V and 28 Vgs=6.00V. These can be used for other SE amp.
On the other hand, there are 8 2sk79. These were purchased long time ago, and were really expensive (all were desolder of some amp, I think). I have not measure them, but I have check that there is diode volt between pins and all are OK. These are very good for single preamp..... The dream of diyers..... all vfets.
Price:
2sk82 and 2sj28 60 eur each (all were tested) + shipping + paypal fees
2sk79 60 eur each (they cost more to me) + shipping + paypal fees

Did a search but did not find the answer.

So, I have built the RSense rig for REW to measure my driver impedance. For modelling crossovers in VituixCad (no TS parameters needed) do I measure the raw driver (on the desk) or in the box (sealed enclosure in my case) ? My instinct say in box but would like to confirm.

Thanks in advance for responses.

Hello, I have already been told that I have constructed too many speakers and am not allowed to build any more…..so I thought I’d join the community.

My first build was in 1985 when I built a box that filled the entire hatch of my Mazda 323 for after market 6x9s from Radio Shack. If I was careful, I could just barely fold a sleeping bag to fit in the back.

My most recent build….still tend to build them big.

Hello, very glad to know you, and thank you for the place especially this audio forum where i've been know before. I like class AB amplifier like gainclones, discretes by Douglas, Apex, Mike B symasym, etc... God bless to you all....thanks

I am Nick, I am opening a coffee and bar business soon, I wanted to create the sound systems myself since I have specific needs that no one can fulfill in my area. I started reading and watching videos about sound systems and they are really fascinating. I was looking for some time for a place to ask some opinions about the system I want to create and I so relieved that I found this place!

I might buy one of these: https://www.ebay.com/itm/115857687208?var=415953468368 to boost line level to use with a Leslie speaker. Any idea of how to hack in a gain pot? I'm kind of a novice compared to everyone on here, so please be kind!

2 x SB Acoustics Satori WO24P-4 in Switzerland.
In original packaging, never used, approx. 1 year old.
190 CHF / piece + shipping.

Hi, If anyone has a Heathkit WM 4 they aren't using, I would like to purchase it. Thanks, Evan

We have a lot of books floating around at work. I thought this ad from the early 60s was pretty cool.

Dear All

I am new for DIY the tube amp.

Now I've already finished the PCB with the circuit as in the attached file.

After I try supply the AC power 220V to it, the problem happen when I adjust the volume of input signal from 0 to max.

There is noise during the volume is middle position ( between 0 - max position of POT ) and I measured grid bias of EL84 it drop below -12V ( -16 ~ -23V) which is happen when middle position of POT. The bias is fixed when I adjust the volume POT it will be changed ?

Could you let me know what is cause of this problem ?

Thank you

I'm trying simulations for converting 3-way speakers to 3.5-way. I couldn't find any guidance about it via online. So, I just did it my way. And, I need advice from experts to consider whether my design went correct way or not.

Let's start with the original 3-way system.



Note: the woofers are set the SPL at 74dB (-6dB from 80dB) in order to exhibit the graph was tuned flat. But the spike at 2.5kHz was intentionally left because of my preference.

What I did for the conversion was I doubled the inductance and halved the capacitance on the low-pass filter of the upper woofer and added twice larger inductor to the lower woofer, as seen in the picture below.



The criteria randomly set by myself was the attempt not to let the upper woofer's response exceed the original woofer's region. As you can see, the upper woofer, purple line, won't go higher frequency than the original woofer's response, red dotted line.

The green dashed-dotted line is the response when the original woofers were played at their actual level, woofer's SPL at 80dB (not at 74dB) equals to midrange's and tweeter's.

Finally, the impedance plots are shown below.



Are the frequency response and the impedance response presented acceptable?

Hi Everyone

I've had a Technics SLP-310 CD player for many, many years which my wife bought me when CD's were a novelty. The unit works perfectly once I have left the power on for a few hours before use! When switching on, the laser seems to scan the disc but doesn't indicate how many tracks and the disc duration after the initial boot up. When I leave the unit with the power switched on for a few hours and then return to put the disc in the drive it reads and plays perfectly.

Can anyone explain what may cause this and also if there is a solution to rectify the problem. I've cleaned the laser lens and had capacitors replaced by an audio engineer but he is at a loss regarding the cause.

Obviously, the laser head works otherwise there would be no sound after the extended warm up scenario.

The sound quality is superb through my Quad 33/303 and Spendor BC1 system and the unit has a sentimental value as well so I am loathe to purchase another CD player.

Any help and advice anyone can offer would be most welcome.

Thanks in anticipation.

Chris

i'm Tobi from Germany. My main interests are tube amplifiers and generally older audio devices including speakers from Grundig or Dual, for example. I'm just getting back into tubes, so please bear with me 🙂

I have a meat cleaver that belonged to my Grandfather who was a butcher starting around 1900. It probably was sold through Sears And Roebuck catalog sales. The marking is "Craftsman Professional".

I also have a Wok that I bought back around 1978 when I was in college at Clemson Univ (SC). It is great for oriental food,and does a jam up job for popcorn.

I have always wanted to learn analog design, at least to the point where I could tell whether a piece of gear is really valuable or just marketing hype. To be honest, I never succeeded.

I hope that this time, I can get a better result by learning from the community and hopefully not ******* off my wife too much with all the resistors and capacitors I need to stock up on 🙂

Hello everyone,

I had a relatively nice audio system many years ago, bit a little earlier this year I caught the bug back and started building a system again. It started with building CSS-audio TD1X speakers and putting it in a system with a Mac Mini as a source (Apple Music) feeding a Denafrips Iris DDC => Pontus II 12-1 => Ladder Bach preamp => Arcam PA240 power amp. I recently bought a pair of Musician knight 1 speakers (which sound great!) and have ordered a Denafrips Athena preamp which is on the way.

I want to try a different streamer than the Mac, so I built a streamer based on a Raspberry Pi and Iancanada’s components, but have trouble figuring out the I2S pinout, and will start a thread to ask the question in the right forum.

For now, glad to be part of this community and enjoying this hobby!

Hi! I am Abhi from Dubai. Looking for Advice on DIY upgrades for amps, DAC & Speakers.

Look forward some great intel!

Thank you!

Hi, Im here for help on a 6-24 crossover and honey badger projects.

Goodday all,
I am looking for a Triac replacement for a Smor5g42, It is part of an X drive like Carver is using in their power supplies, I think it is a 500mA jobbie.
Help appreciated !
Regards
Jan

So, hey guys, Im still in the testing and prototypeing phase but i finally finished testing all power source solutions for my Aleph-3 build. The best configuration that makes this amplifier sound absolutely magical is one transformer, two rectifiers, and two capacitor banks. This type of Class A amplifier is incredibly influenced by the power supply, and you can wire it in the most common three ways:
1.A single transformer, one rectifier, and a big capacitor bank: This setup will give you the worst bass possible, a very flat center image, no layering, and absolutely no body in the sound.
2.Two transformers, two rectifiers, two capacitor banks: This setup is very problematic because if one of the transformers is not on the same phase, the sound quality is absolutely gone, and it won't sound better than a cheap '80s or '90s amp. But if they are in phase, the sound quality is decent but not great. The soundstage is there but not precise, you can't pinpoint details, layering is really weak, and the body is still missing.
3.The overall WINNER: one transformer, two rectifiers, and two capacitor banks: This way, the sound is absolutely magical. Precise, pinpoint accurate imaging, fabulous layering, and incredible body to all sounds. It simply becomes that amp that you can't turn off. This configuration also has some downsides: the rectifiers get hot, and the transformer needs to be big. Oh, and under no circumstances should you use a CLC or CRC filter in this configuration. I find it pointless and, in some songs, it ruins the guitar sound magic (e.g., Buckethead songs).I can go into more details, but if you are a real DIY person at the beginning of building one of these, just do it as I say and be amazed. Of course for the final build I will use super fast diodes and decent capacitors .Any comments are greatly appreciated. Peace!

Hello,

Some time ago changed NAD C165 pre-amp Volume potentiometer. As always, affordable potentiometer was standard with 3 taps. Original potentiometer has 4th tap. After the replacement Tone control is not working.

Has anyone found a custom solution for simulating 4th tap? Not expecting the full operation only to get Tone controls back to working at some level.

Hi everyone, I have a mini dsp that I want to use to bi-amp some speakers. I have some powersoft digimod 1000 and 500 that can be used both unbalanced and balanced, but the output level of the Mini dsp with an RCA connector is too low in terms of volume to be able to drive the amplifier. I tried some adau modules from sure and the result is the same. Where can I buy a PCB that acts as a preamplifier between the DSP and the amplifier? AliExpress? How should I search? Do you have any links? Thanks

Hello guys,

I`ve been dreaming for a long time on a nice balanced preamp that can drive directly a power follower.
Lately @Zen Mod offered both the nice preamp, the Iron Pre, and also a lot of power followers from which one in particular caught my attention and that is Plethora of Pinjatas .
Slowly but steady I managed to draw a pcb for the IP and mount it in my UGS Pre, obviously the idea was implemented with the help of Zen Mod.
Now I want to start drawing the pcb(s) with the OS of Plethora of Pinjatas but not being sure if it`s going to work I asked Zen Mod about it and on his advice I started this thread.
So again slowly(I have close to 10 years since I dream about this) I started to copy the schematic of Plethora of Pinjatas OS and to make the pcb.

To mention that the dimension between the holes of the mosfets in my case is 15cm, I don`t use the standard UMS.

If I got it right I need 2x OSes, to the input of the first OS(R125) I will connect the positive output of the preamp and to the input of the second OS(R125) I will connect the negative output of the preamp. From the positive OS I will take the + signal for the speaker, from the negative OS I will take the - signal for the speaker, correct?

Now how can I adjust the offset? Is it ok to use same config as Sissysit 42? What will happen if I have the preamp dc coupled and the input of the OS(R125) is not at 0V?