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I see what you mean, but I was looking for clipping not in the power amp circuit itself, but specifically if the line output was being clipped by the LED conducting. In the circuit it's wired the same as you would a clipping diode in a distortion circuit, so I wondered if it would have the same effect. But it seems not?

You will need a series resistor to "Clip against". Let's say that when that LED turns on it draws an extra 20mA- the SS amp can easily supply that and keep the voltage from dropping. The Feedback around the SS amp allows it to compensate. The series resistor Isolates the feedback loop from seeing the non-linearities that you are looking for.

Great job man!

Are those non-polarized caps?

Be careful when bringing your load box up to 450W. PCB's may or may not be able to handle that. I recently rewound an OPT that arced because the load box built on a PCB failed and opened up. When you are running flat out, and the load opens up there is a good chance you will nuke your power tubes and also a good chance you will arc your OPT. Maybe an IR heat meter can tell you if your traces are getting close to maximum.

Dear xbearxau, Perhaps you can post the parts list that you used with links to where you got the various components?
Thanks!

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Looks great! I'm curious if the line out sounds any different because of the different line out transformer you used. My original Suhr seems to be a bit lacking in deep low end.

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Sounds good, and the build looks good!
I find it Interesting that, compared to the Aiken load design:
- There is no resistor parallel to the bass resonance L & C in the Suhr design to limit the bass resonance peak. Perhaps it is not needed because of the internal resistance of the bass resonance L and C, or something to do with this L saturating because it is not an air coil?
- There is an extra C (C2 22nF) parallel to the treble peak R & L circuit. Perhaps this limits the high frequencies above 5kHz in this treble peak circuit?
- L2 is rather low at 6,8mH, I expected something like: 50mH Aiken design at 16 Ohm => 25mH at 8 Ohm. But when a speaker is mounted into a cabinet, the resonance peak should move a bit upwards from 75Hz to 100Hz or 120Hz, so the L value should be lowered a bit. That's why the "adjusted" Aiken design at thegearpage uses 10mH or 11mH for L2 (parallel to 200uF).
See also:
https://www.aikenamps.com/index.php/des ... d-emulator

https://www.thegearpage.net/board/index ... d.1072793/

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Yes, without that R, the bass resonace peak should become higher.
Please, what do you mean with "low mid peak"?

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Very impressive build, and the sound's amazing ! Like floris, I'm interested in the part list. Also, is there any difference with the wiring diagram of soulsonic ? Especially for the grounding of the jack inputs.

As well interested in parts list Have been doing lots of research on these Reactive boxes and of course building my own as we speak. Have ventured into the ones that are of high interest that would include the Surh RL,Weber Mass,Two Notes Torpedo Live,Fryette PS2 and newer 100. and possibly Rivierra Rock Crusher and Universal Audio RL Speaker modeling. One thing have found about all of these (I think ) is that when using these for IR's many don't realize that they are using the Line Out and not the Attenuated out as the signal to the interface. You can actually use the box without even turning it on and still get a line out signal to the interface. So my questions to the board are 1;) Can you use the attenuator or RL to get a dimed signal to the interface /IR and can it be reactive using RLC circuits ? Imo lots of these people using these boxes aren't aware that they are not using the attenuator as their signal to the interface but using nothing but a purely resistive voltage divider Line out.
One more question is if you use an attenuator for sending it to the interface at what point does it become to big to start frying stuff ?

Ampkat, The reactive load ensures the amp "thinks" it is connected to a speaker, so that the amp behaves as we want. The signal on the speaker output of the amp (not the speaker output of the attenuator) is the correct one to send to your speaker IR, but this signal is too large for an interface/IR-pedal so it is made smaller by the passive resistive voltage divider on the line out.

Floris yes true but that is not what people think they are getting. Lots of Videos like ones by Pete Thorn where he is telling people he uses his amp then the attenuated reactive load then sends that to the interface. Where the reality is you don't send that attenuated signal but rather the line out signal that is connected to the speaker input and in fact you don't even need to turn the unit on to use the line out .

Just wondering if you used the speaker out from the attenuator at what level could you use it into the interface ? If you attenuate it down to say +4dBu it would be small enough to not fry the interface.

"... you don't even need to turn the unit on to use the line out ."
The line out will work but the amp needs the reactive load to sound good with the right frequency spectrum. So you need to turn the unit on if you don't use a speaker cabinet.

"Just wondering if you used the speaker out from the attenuator at what level could you use it into the interface ?"
Do not use the attenuated speaker output of an attenuator-box for sending the signal to the interface. Use the speaker output of the amp itself, reduced via the line-out/DI-out of the load-box. This is why the line out resistive voltage divider is connected to the input of the reactive load-box which is connected to the speaker output of the amp.
Btw, the Suhr reactive load-box has no attenuated speaker output, it's only a load-box for the amp not an attenuator-box.

"If you attenuate it down to say +4dBu it would be small enough to not fry the interface."
Yes if your interface can handle +4dBu signals.

floris wrote: ↑07 Jan 2021, 20:02 "... you don't even need to turn the unit on to use the line out ."
The line out will work but the amp needs the reactive load to sound good with the right frequency spectrum. So you need to turn the unit on if you don't use a speaker cabinet.

That's the part I don't get because you aren't using the reactive load when using the line out you are bypassing it !! The only thing the power does is run switches and or relays. Everything else are passive components and need no power at all.

Don't get why you need a $700 box to use a line level output that is bypassing the attenuator. If you are using the speaker thru and then reamping yes can see that. But I can get the exact tone to the interface with a line out and my $5- 8 ohm 100 watt resistor and the line out. The reactive load is only good if you want to run a speaker .

The signal from the speaker output of the tube amp is different if it is connected to a reactive load, instead of a resistive load. That is because the tube amp output, which is relatively high impedance compared to transistor amps, "works together with" and is affected by that load. The line out circuit must be connected to the speaker output of the amp (= the same as connecting it to the input of the load box). The reactive load is not bypassed when using this line out, because the tube amp's speaker output signal is affected by this reactive load.
I hope this helps...