Two PT in parallel

[GERPUD]

Thank you guys for the ideas!!

Actually, I was thinking that it would be really cool of building an unleach badcat even before I saw Matt H post! You read in my mind!

Is there any DIY kit available to do this Unleach Badcat equivalent?
I wouldn't need the attenuator part, but only the re-amplified part.
By the way, what is the exact name for this device? Re-amplifier?

For the whole amp, it's on my "to do" list, but not right now.
I know SE is harder to modify, but I really like the sound and the look of this amp. If I can fit a Re-amplified device, this amp could be really surprising!

[matt h]

(deleted)

[GERPUD]

They are selling a cheaper alternative than the Badcat:
http://hoelectronics.com/wordpress/138-2/

We can see inside. Looks dam simple. Anybody recognize the internal parts?
Would be a great DIY projet for me!

[matt h]

(deleted)

[The Ballzz]

Thanks again
But I'm sad because now I need to find something else to modify!

Why don't you go all the way and plain build one amp ?

The "ultimate Mod" : going from a bag o' parts to a working amp!!!!

For the first one, get a kit, mainly because sourcing parts all over the place is tedious .

You will learn, of course you will enjoy it, and Modding something you know so well is easier.

Rather than a single ended amp, which is a "stiff" design, very hard to Mod for higher power; build a push pull one.

Something with 2xEL84 is fine, even better something with 2 x 6V6 because being octal sockets, they will also take 6L6, EL34, KT66, KT88, etc.
Just what you were trying to do

Only precaution is to order , just from the beginning, a power transformer with filamet windings hefty enough to feed the largest tubes, plus any preamp tubes you fancy to add later on.

You can also use a beefy separate filament transformer.

Best of both worlds.

What He Said TIMES 10! But be forewarned, a first time successful build WILL induce an addiction worse than heroin and totally beyond cure, especially if you are truly a player and tone seeker!
Excuse Me While I Fire Up My Needle (Oops, I Mean Soldering Iron)
Gene

[The Ballzz]

A BadCat Unleash works basically as a dummy load for your main amp with a line level out (allowing you to have your main tube amp cranked to your desired sound, but not driving any speakers from it) to a solid state power amp with it's own volume control that drives your speakers. This same concept can be accomplished in several different ways:
A) Use a dummy load on the speaker out of your amp and use either a direct box/DI on the output of the dummy load to drive any poweramp>speaker.
B) What I do is I use a Weber attenuator (it's attenuated speaker out driving one speaker) that has been modified to take it's line out signal after the attenuation to the input of my rack mount effects unit, with the output of the effects unit driving the input of a solid state amp into another speaker.
Gene

[GERPUD]

Gene: "But be forewarned, a first time successful build WILL induce an addiction worse than heroin and totally beyond cure, especially if you are truly a player and tone seeker!"

I know, but having an addiction is in the human nature. I don't know anybody that is not obsess by something: sport, esotericism, facebook, photography, animals, porn, drugs, visual arts, etc. The gold is getting a obsession that does not creates a problem with your wife, familly, friends, or budget. At best, it should stimulate the body and mind. So, I believe that tube amp mods is a healthy obsession.

Right now, I don't have the time to be involve in any obsession at all. It's going to be my first one as soon as I get more free time!

For the Unleash, it seems, from the pictures I've seen and what I've read, a class D Mosfet amplifier. So it turns a full tube amp into a preamp of bigget a solid state amp.

HO electronic does not seems to be a Class D.
http://hoelectronics.com/wordpress/138-2/
There is no low pass filter. Also, I read that it is hard (impossible) to make a good Class D by hand without a tight PCB. This re-amp must be transistor Class AB. Don't know if it would does a better job...

[Jana]

matt h,

Whether or not your idea of an OT connected in reverse is a piece of the Badcat, this idea does open up some possibilities.

If an OT were connected to the amp speaker output as a load, then the secondary (which was the primary) would need some kind of load on it in order for the correct 8 ohms impedance to be established. Let's say you took an OT that was normally a 5K to 8 ohm unit. Now, connecting the 8 ohm up to the speaker output of the amp, we need a 5K resistor to establish the 8 ohm load.

But, since we have now converted the low impedance, lower voltage but higher current of the the amp's speaker output back to a higher impedance, higher voltage but lower current configuration, this makes it easier to do some filtering.

My point is, it should be easier to create some filter networks in that "5K load" to help simulate the curves of speakers, cabinets, etc. It still most likely will not sound like a true speaker cabinet that is moving air and rattling windows, but I suspect it will be much closer than a pure resistive load.

[JMFahey]

Ho's is the original all-in-one "active attenuator" , meaning load > signal attenuation > maybe some EQ > SS power amp.

It had been done "by hand" many times before, but with separate components, and of course many amp loads/attenuators included a "line out" , usually meant to go straight to recording/PA mixers ... nothing stops you from going to a power amp instead.

What Ho did was to provide all this in a single , easy to use box.
As he told once, "somebody" whose name I don't remember now bought straight from him, and resold them in USA under the brand "Ultimate attenuator" ... or something like that, just quoting from memory.

In my personal view, the Unleash is basically the same, only with a digital amp instead of a conventional AB one, and including an effects loop.

And the Ho "Tone" box looks like a very simplidied, no controls Attenuator, set not to attenuate but to add a little extra power.

What baffles me is that I see 2 transformers, one must be Power but .... the other?

WAY too large for an input one, might be an output one ... perhaps to adapt for a different impedance?
Just guessing.

I also can't see the input load resistor which would be needed to absorb the driving amp power out.

That said, I have a vague idea about how it might work, mainly letting original amp power pass through and beefing up available current with the transistors.

But in that case, it might turn, say, a 50W/8 ohms amp into a 100W/4 ohms one , by matching current from the original amp and adding same amount ... think paralleled chipamps.

mmmmmmmhhhhhh , not thinking about it often works, a"click" and understanding often comes apparently out of the blue.

[GERPUD]

If HO is, like you said, adding by transistors power to the real output of the amp through Class AB transistors, that sound a way better idea than attenuate everything and then reamp everything with a class D like the Badcat Unleach because you will still have a fraction of the sound that is "original" or "pure".

I'll probably call him tomorrow. I'm too curious.

[shane]

Kevin O'Connor used to do things called Super scalers. have a look at the London Power web site about those.

In one of the TUT books (TUT5 maybe?) he gives details of how to build a simple tube based one.
It could produce about a six fold power boost that was tonally transparent. and very easy to build.

It was a class B design using 6L6's with grounded grids and the output tubes driven via the screen grids. quite cool really. Requires a small output transfomer to drive the output tubes and a larger output transformer.
The unit has no controls except input and output impedance switches and goes between the small input amp and the speakers and is set up so the smaller input amp 'feels' the speaker load.

I built one and it worked very well, quite transparent as claimed.

The Ho one looks kinda like a similar thing but with Mosfets instead of tubes.

Cheers
Shane

[matt h]

(deleted)

[M Fowler]

I posted these Unleashed photos a while back.

https://tubeamparchive.com/download/file.php?id=30954
https://tubeamparchive.com/download/file.php?id=30955
https://tubeamparchive.com/download/file.php?id=30956

[GERPUD]

Shane
Could you post the schematic of the device you are talking?

[shane]

Hmmm. I'll have to have a think about that.
As a licensed power scaling installer for Kevin I am hesitant to be posting stuff from his books.
I'll have to see if I can post something similar, leave it with me

Cheers
Shane