Early 90's Bogner XTC 101B Attenuator Loop?

[67Mopar]

I recently purchased a 1994 Bogner XTC 101B white chassis w/dual assignable cabinet select. The icons that indicate it's production #068. It has an "attenuator loop" that I can't make heads or tails of? There's a red washer marked "line-out" output just underneath the attenuator loop. I can only assume that this on-board attenuator loop is meant to be used with the line-out option? It looks like it's assignable to each channel also via push-button switching. I just can't imagine that it would work any other way than through the line out. But does that mean "line-out" isn't line level? I'm totally stumped!

I've owned several later model XTC and Shiva amplifiers, but this amp sounds SO much better than any other Bogner amps I've played/owned. I just want to be able to have a full working knowledge of this amplifier. I asked Charlie at Bogner about it, but he couldn't give me a definite answer as only 50 of these were ever made. He did tell me to "hold on to that amp!"

[ryu]

hi, I've found this

"Obviously it's there to work with a soak of some kind like a Hot Plate. It's only available for one of the speaker outs. Not sure which but that's easy to figure out. It also has to be assigned to the different channels but pressing OUT the button in the top right hand corner of the block for that channel (just to the left of the attenuator input and output).

The funny thing is, the "Input" and "Output" labels are kind of reversed. They don't label what they do, they label what you connect the other end of the cable to. So you would connect a cable from the amp where it's labeled attenuator "input" to the Hot Plate's input. Then you would come out of the Hot Plate's output and connect it to the jack on the amp labeled attenuator "output". Kinda messed up. Usually an output of one device is connected to an input of another device. Anyway, it's a cool feature on this 101B that you can't get anymore. The ability to have two different cabinets at all isn't even available now."



idealy a gut shot would be nice, maybe we can figure out why this one sounds "better"

[joey]

I'm thinking it was a brief collaboration/licensing between THD and bogner. It's really just an attenuator most likely a 16ohm one to match bogners cabs, with a line out functioning as a loop send/slave out. You could then run effects post power amp, and then re-amp them into a dedicated pa. I'm thinking it was more intended to be used in plexi mode, where this would be most beneficial, especially since it was implemented during era when it started to become common knowledge that A lot of "pros" did this most reputably evh.

I can see why it was dumped in this amp though.

[67Mopar]

I meant that it sounds a lot better than the 2006 and 2007 model XTC's that I once owned. These are keepers!

Thank you for your insight on this. I want to learn as much as I can, as I don't want to damage the amp by making wrong connections.


The 101B cab-switch option is just about the coolest thing I've ever encountered in an amplifier. Very cool idea!

[67Mopar]

hi, I've found this

"Obviously it's there to work with a soak of some kind like a Hot Plate. It's only available for one of the speaker outs. Not sure which but that's easy to figure out. It also has to be assigned to the different channels but pressing OUT the button in the top right hand corner of the block for that channel (just to the left of the attenuator input and output).

The funny thing is, the "Input" and "Output" labels are kind of reversed. They don't label what they do, they label what you connect the other end of the cable to. So you would connect a cable from the amp where it's labeled attenuator "input" to the Hot Plate's input. Then you would come out of the Hot Plate's output and connect it to the jack on the amp labeled attenuator "output". Kinda messed up. Usually an output of one device is connected to an input of another device. Anyway, it's a cool feature on this 101B that you can't get anymore. The ability to have two different cabinets at all isn't even available now."



idealy a gut shot would be nice, maybe we can figure out why this one sounds "better"

Here's my email response from Jorg at Bogner:

My question:
"I was also curious to these "tone suck" comments on the forums in reference to the early white chassis 101B model Ecstasy amplifiers. I have a 100B and a white chassis 101B with cabinet switcher and attenuator loop options. It's one of the best sounding amplifiers I've ever owned, and sounds just as good (maybe even better) than my 100B. I'm just a bit confused as to what these people are referring to?"

Jorg at Bogner:
"The cab switching is done with relays so the audio signal goes over the relays which migth or might not suck tone. Neclegtable in my opinion... These are very expensive huge relays. It's just something for people to talk about, I would not worry about it..."

[ryu]

ok here's my opinion, first, the circuit of 100b and the 101b is not the same, some people liking the 100b might not like the "new" circuit, as they aren't aware of the circuit differences, they look at the back panel and see there's a new speaker selector option and blame it
about guys with a newer one, the plate's resistors used to be metal film (rn65 or rn70 I'm not sure so far)at some point they've changed for carbon film, same value but different sound, same comment as above
I've done a lot of swap and I prefer carbon even if they're a bit noiser, this is debatable to death (fender vs gibson etc), FYI an amp guru mister "D" used to use those resistors on plate too
so maybe you like metal film on plate better
post 2004 they've added a gain mod, unneeded IMO

that said, it would be nice if we could see inside, all you have to do is remove the 4 screws under your head cab, make sure not to touch anything inside the chassis (you might get shocked) and post some pics
if you do so, please check what says the back of the two gain pots and the back of the two masters, if it's 500k or 1M
jorg swore they've always been 1M but a lot of people reported it being 500k too, this might change the sound
tone conrols should be 1M, 250k and 25k but it would be nice to know if there's a A or B after the value too see if it has been changed or not (compared to the newer one I had)
edit : 25k presence pot too

[67Mopar]

ok here's my opinion, first, the circuit of 100b and the 101b is not the same, some people liking the 100b might not like the "new" circuit, as they aren't aware of the circuit differences, they look at the back panel and see there's a new speaker selector option and blame it
about guys with a newer one, the plate's resistors used to be metal film (rn65 or rn70 I'm not sure so far)at some point they've changed for carbon film, same value but different sound, same comment as above
I've done a lot of swap and I prefer carbon even if they're a bit noiser, this is debatable to death (fender vs gibson etc), FYI an amp guru mister "D" used to use those resistors on plate too
so maybe you like metal film on plate better
post 2004 they've added a gain mod, unneeded IMO

that said, it would be nice if we could see inside, all you have to do is remove the 4 screws under your head cab, make sure not to touch anything inside the chassis (you might get shocked) and post some pics
if you do so, please check what says the back of the two gain pots and the back of the two masters, if it's 500k or 1M
jorg swore they've always been 1M but a lot of people reported it being 500k too, this might change the sound
tone conrols should be 1M, 250k and 25k but it would be nice to know if there's a A or B after the value too see if it has been changed or not (compared to the newer one I had)
edit : 25k presence pot too

I will take some pics today or tomorrow - then post them.

As far as comparisons between the early white chassis 101B and 100B, I don't really think one sounds "better" than the other, so my choice of words were selective. The biggest difference is that the 101B has a more versatile clean channel compared to the 100B - but I like them both. The 100B is a more pristine type clean vs the "breakable" clean of the 101B. I like to use a BB preamp and KLON on the 101B clean channel.

Reinhld Bogner apparently used two different OT's on the 100B's. Reinhold seemed to prefer the ones without the housings, as he has 3 of these in his personal collection. He recently loaned one of them to Joe Bonamassa. The first 10 or 12 100B's were fitted with these OT's, as were a few later-on the 100B series. Mine has one of these also. Did I get lucky?

For someone to get on the TGP forum as "squarehead" did and tell players "not to buy the 101B amp" is totally without merit! I think people who make these types of comments have never played most of the amps they tend to critique. I use both heads daily, and while there are differences between the 100B and early 101B Ecstasy amplifiers - one certainly does not "beat-out" the other. The 100B is a bit more "live" sounding - while the white chassis 101B is a more "studio" sounding amp. If that makes any sense?

Here's a pic of the OT I mentioned. Jorg was surprised to see it, as he didn't know that Reinhold had put these in any of the later 100B models.

[67Mopar]

I figured-out how to use the attenuator loop - should anyone care to know? You have to use speaker output #2 - not #1. It is the coolest damn thing I've ever seen in an amp! I can set whatever channel I wan to run with the variac. Sound absolutely fabulous!

\

[ryu]

metal film on plates,I told you

you too have an empty spot besides the last stage cathode
just like in this 100b
http://img195.imageshack.us/img195/1563/bog100b.jpg" onclick="window.open(this.href);return false;
it's been a while that I wonder if he used to use a bypass there on earlier models(.68u, 1u?)
please may you take a pic of yours (100b)
http://img207.imageshack.us/img207/2070/bog100b2.jpg" onclick="window.open(this.href);return false;
I'm particulary interested in this resistor and cap value, this one has 2,2k(?) and probably 2,2uf but I think it has been hacked a bit so I'd like to be sure

[joey]

metal film on plates,I told you

you too have an empty spot besides the last stage cathode
just like in this 100b
http://img195.imageshack.us/img195/1563/bog100b.jpg" onclick="window.open(this.href);return false;
it's been a while that I wonder if he used to use a bypass there on earlier models(.68u, 1u?)
please may you take a pic of yours (100b)
http://img207.imageshack.us/img207/2070/bog100b2.jpg" onclick="window.open(this.href);return false;
I'm particulary interested in this resistor and cap value, this one has 2,2k(?) and probably 2,2uf but I think it has been hacked a bit so I'd like to be sure

The old 100b is nearly verbatim the new classic model sans the Metal Film Resistors. The only difference is the 2.2K cathode resistor instead of the 2.7K which is negligible, and 2.2uf bypassing it. Other than that it's not different besides the layout, which will make the biggest difference. The bypass was most likely for experimentation since this amp was born from the Brown channel of the fish, which has the last stage bypassed, no xtc I have seen has this, if any of the really oldest of the old do have one it would be a white .68uf.

The Pots have always been 2X 1MEG in parallel. at one point I had the factory scheme for it, and the uber, and the factory schemes have always matched the real deal.

[ryu]

thanks joey, do you know if the 100b as the 499k to ground after the master too? I did that 100b mod to my amp a while ago and I did prefer it to the 101b specs but with the 499k it thined out single notes too much and without the sound was cool but it was a bit too dark (not cutting enough) for my taste

do you know what the air switch does? I'm guessing it parallels the missing capacitor and that's why everybody says it's subtle

[joey]

thanks joey, do you know if the 100b as the 499k to ground after the master too? I did that 100b mod to my amp a while ago and I did prefer it to the 101b specs but with the 499k it thined out single notes too much and without the sound was cool but it was a bit too dark (not cutting enough) for my taste

do you know what the air switch does? I'm guessing it parallels the missing capacitor and that's why everybody says it's subtle

The classic certainly does. Keep in mind that the mv's are also 2x1meg in parallel. The 499k to Ground right before the pi messes with the sweep, tone stack response, and source impedance to the pi when the loop is out of the circuit. If you only have one MV, I wouldn't even bother with it and just use a 500k pot instead.

[ryu]

I had 1MA master bypassed with 1M resitor to be "as close as possible", then I tried with and without the 499k to ground