I've been mostly out of the audio hobby for a while, but I've had a few inquiries about the SemiSouth version of the Amazing FET Circlotron as of late. So, I wanted to post the performance graphs here before I lose them.

It seems I have been doomed to not do any of my DIY projects since my main computers hard drive crashed followed shortly after by my laptops (the laptop has had another crash after that, and the drive is now on the way out again!!)

After having to pull the cables out of my chipamp last week and plug the TV into it (because the MythTV box refused to play a DVD and I can't plug the DV18 DVD player direct to the chipamp because it has no volume control) I decided I had better get off my backside and finish my pre/active crossover. I had to do it again tonight as well (plug the tv into the chipamp), sigh...

This is all because my playmaster had something in the pre die again and is only working on one channel and I just haven't been bothered fixing it. I thought that being inconvenienced might make me more likely to finish the other projects but it has been broken for about 6 months

So on Monday I decided that I should re-install Holm-Impulse...

I just built a Distortion Cancelling Push Pull (DCPP) amplifier designed by Peter Millett. It sounds very nice, was fairly easy to build, and is rather inexpensive. Thank you Peter for the great design!

I acquired a TD-124MKII back in late September and after some months feel like I have come to some understanding of its strengths and weaknesses.

I finally understand that the drive train will never be silent, and needs some periodic maintenance to perform quietly.

Belts are problematic on the MKII, and later versions of the MKI with the dual in chassis intermediate pulley. For some reason very early units seem quieter in this respect.

Motor rebuilding is pretty worthwhile, mine of course was not running so it was mandatory. My experience with motor bearings is limited, but based on replacing a number of bearing sets I would recommend the bearings available from The Analog Depot over others I've tried. They are very precisely made and run well from the get go.

I've added a Bren1 record weight which I feel clamps the record more effectively to the table's moving mass, and I thought improved some areas of performance significantly. Bass...

Hello guys,

I was wondering if any genius out there who knows about preamp circuit who can explain this one to me.

See I am just getting into audio systems design and I am try to understand this preamp circuit and how it works.

A few questions:

1)what does the two cap in series does and why are they connect to ground?

2) what does R3, R1 and R2 does?

3) What is the uses of the polarity Reverse?

I have been reading up on these component but i am a little slow on understanding.

I would appreciate the help.

Hi I'm new here and hope you can help me.

Currently I am workingwith thecircuitIraudamp7Dwith theblockIRS2092. Unfortunately I dont understand with which type of modulation this circuit operates. In the datasheet of Iraudamp 7D is written that it is powered bythedelta-sigma modulation. But I not see the dealy flip flop. And the clock is with 400 Khz very small for Delta Sigma.
Can You confirm that this is by delta sigma?

for your help I would be very grateful!

Sorry for my bad English im from germany.

Iraudamp 7D: https://www.irf.com/technical-info/re...iraudamp7d.pdf

IRS2092:https://www.irf.com/product-info/data...ta/irs2092.pdf

How many posts, describing the sound of something, have the caveat, "...in my room"?

My listening space/room is a subset of the upper floor of my house. All the volume of this space is fairly open and interconnected acoustically.



The space is nominally 24'x36' (houses in Canada are still built in imperial units) surrounded by deck on 3 sides. The peak of the roof is at 2/3 and rises 17' at the highest. It slopes down over 24' to ~6.5' over the main room. An 8' x 12' section is divided off for kitchen with the bedroom above.



The rest of the space is 12'x24', raised 42" above the main floor and has a roof (mostly) that vaults from 8' to the same peak (just over 12'). The main space & this space are connected by 2 -- 3.5x7' openings and 5 -- 16"x2.5'...

Before describing the changes brought about by the mods I've described, here's a summary of what they've been:

• Crossover tweaked to flatten the lower end bass hump and knit the handover to the tweeter more tightly
  
• Power amp sensitivity reduced to allow the volume control operate closer to maximum with my Asus soundcard or a standard CD player output.
  
• Rectifier snubbers and additional filtering to the regulators fitted to reduce RF ingress on the power supplies.
  
• Power amp supply decoupling improved at both LF and HF.
  
• Signal grounds are now separate from power grounds and a star point established on the amp PCB. A ground loop between the two PCBs has been eliminated. The input signal ground is no longer connected to the tone control PCB ground - instead given its own dedicated wire to the star. Decoupling to ground on the tone control PCB has been removed.

Listening impressions

OK, so on to the part that you've been...

hey please help, in ma ruby amp, all other circuits are working but can't give input to it..please help???

This thread.
https://www.diyaudio.com/forums/solid...tp-choice.html

Sources:

https://www.utsource.net/index.aspx

https://www.taydaelectronics.com/servlet/StoreFront

Sadly the 2SC2240 and 2SA970 (npn, pnp) super-low-noise trannies in TO-92 packages no longer appear on Toshiba's Bipolar Transistors Product List, and have been designated NRND by Toshiba (Not Recommended for New Designs). [link] This means the factory is presumably still taking (large) orders, but they are destined for the dust-bin of history. FYI, last chance, B&D still has some inventory.

But, not to fear, Toshiba offers what appears to be the same (or better) die in SOT-23 packages, the 2SC3324 and 2SA1312. These are stocked by Mouser, and cost only 15 cents qty 100. Their datasheets are fairly complete, including two NF contour plots. The 1kHz plot shows the 3dB contour dropping 35 ohms at 1mA and below...