Tube Amp Archive

It's probably AI bots constantly going through the forum posts. I have the same problem on my server and I had to block all IP ranges from China and Singapore to get rid of them.

C6 and C7 are power supply filter caps. They can be smaller. C5 is there to block DC current from going through the output transformer.

RV1 is a bias balance pot. If the triodes in ECC82 aren't matched well then the compressor might thump and RV1 can be used to adjust the current difference. RV2 is output volume pot. Center taps of the transformer should be left unconnected. I updated the first version of the compressor so it should...

In the second version there's a 24V linear regulator to get the right voltage for the tube heaters and the sidechain. The sidechain requires about 24V voltage supply. The DC-DC high voltage power supply needs to be able to provide about 5W of power. With 250V the current consumption of the B+ supply...

It's a simplified version of a studio compressor circuit. It's a test circuit I made to see if it works well enough for bass and it does. Here's the compressor circuit that it's based on: https://phpbb.ghr.fi/viewtopic.php?t=109 Here's the latest version of the bass compressor schematic with DC/DC p...

Here's a fairly simple tube compressor schematic. It does use an output transformer but a cheap Edcor XMS transformer will work here well enough. About 12dB of compression can be achieved with less than 1% THD and 16dB with less than 5% THD.

Wardy wrote: ↑Sat Jul 26, 2025 2:30 pm Many Thanks,

I also found this simple Valve compressor. Any thoughts on how well this might work? 2 valve compresor circuit.pdf

Where is that circuit from? It doesn't work at all. The idea there is to use ECC83 anode resistance as a variable resistor but the circuit is wacky as heck.

I removed the red and blue from the spade connections and measured 73 ohms, green and black measured 1.4 ohms. I have not found a spec on the resistance for the transformer to compare the results to. Primary resistance on the reverb transformer should be somewhere around 1000 ohms. Looks like the p...

The only problem is that this forum is hosted by the owner at a shared site. The forums aren't on a unique IP and I don't believe we have the ability to throttle/rate limit/block by IP or IP list on the hosting provider side. They're pretty bad. IP addresses can be blocked using .htaccess file. Tha...

If they're doing what I think, all they need is ANY page and the login page is one of them. They can just constantly load the login page and it will slow down the site and cause issues. Due to the fact that the hosting provider doesn't seem to be doing anything proactive to catch/stop this it just ...

Admin of this forum should check from what IP addresses the guests are coming from. Most likely it's net range of 47.74.0.0 - 47.87.255.255 that's registered to Alibaba Cloud LLC. Easiest solution is to just block the whole IP range on the servers firewall.

I haven't been able to access amp garage all day. I think there was some sort of bot invasion going on and not just on this forum. I noticed several forums had most ever users online today.

I've been getting them for a couple of days. I hope someone has a backup of the forum database and files for when this site goes down too.

What kind of results are you getting when you try to model the non-linearities of a system? IME Spice is great for modelling in the linear range, not so great for the non-linear range of behaviors, which tend to be the more interesting operating areas in many applications. Non linear range behavior...

I also tried simulating it with Kicad and it works with spice model from Onsemi. .model BC546B NPN(IS=2.39E-14 NF=1.008 ISE=3.55E-15 NE=1.541 BF=294.3 IKF=0.1357 VAF=63.2 NR=1.004 ISC=6.27E-14 NC=1.243 BR=7.946 IKR=0.1144 VAR=25.9 RB=1 IRB=1.00E-06 RBM=1 RE=0.4683 RC=0.85 XTB=0 EG=1.11 XTI=3 CJE=1.3...