Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on February 18, 2011, 05:30:11 am
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Hi guys, I don't know much about the LEDs. Could anyone tell me is there any particular type used in this circuit.Thanks
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I used Radio Shack Red.
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That is a VERY interesting schematic. Tone stack is very unique also.
I "think" that Johnny A might play a pair of those when he plays live? If I am correct, .... the clean on that amp is really super nice.
I hope you'll record a soundbit after the amp is built.
With respect, Tubenit
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I built a Desktop Series version of this amp (single ended). It has a great distortion tone and the tone stack is very effective. Probably the best from Marshall.
Bonamassa plays one with all the controls at '10'. Big sound.
I've had the 50 and 100 watt versions in my shop and my little beast nails it.
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Timbo check this out some good info there.http://home.comcast.net/~mamp17/Jubilee%20Layouts.html
Bill
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I am very intrigued by this schematic. And don't understand the diodes and LED but sort of understand these to be a version of KOC's poor man's distortion?
It almost looks like the 3rd & 4th gain stages around the "passive" effects loop is sort of turning it into a built in active effects loop?
Is that a realistic way of looking at that?
I'm kind of viewing it like a quasi-sorta active effects loop with a tone stack and volume control on the tail end of it prior to the LTPI??
I am curious about the tone of the preamp distortion? Bonamassa uses so many effects ......... I have no idea what the amp alone sounds like?
With respect, Tubenit
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Hi guys,Your help is AWSOME!!!.TJ that info was just what i was looking for. We have a local electronics store (JAYCAR)and they have the LEDs (Vf1.8/20ma).I think LC might know a bit more on the subject having built a desktop version.I googled Joe Bonamassa and he has a clip on the FX's he uses,also lots of demos on the net.I was going to do a cathode bias version only to be able to use a VVR ( the one i've got only suites a cathode bias) or would it be better to spend the extra and do a fixed bias. Thanks
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That is one trippy preamp I cant tell whats going on in that thing. Whats in use when its in lead mode?
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Its got great tone.
I am curious about the tone of the preamp distortion? Bonamassa uses so many effects ......... I have no idea what the amp alone sounds like?
With respect, Tubenit
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My experience is that diode clipping can be really nice at lower drive modes and begins to be not really noticeable at higher drive and volumes. It also takes off the high end since the clipping flattens out the wave form. I use it at lower volume in a lower powered practice amp at times and removed it from a recent higher powered single ended amp w/ VVR (not practical or wanted/needed). YMMV
It's interesting in that it can help give a smoother type of distortion sound and also reign in parasitic oscillations, but can be a detriment to the way the note(s) sustains also if the forward voltage isn't balanced right.
The diodes' forward voltages that are used in that circuit are what's important as noted in that link but not described. Too much and the signal gets dropped or affected too much, not enough and the effect isn't as good as you'd like. Also different diodes can sound a bit different too. This is "one of the main secrets" when modding a modern/chinese Boss DS-1 effects pedal to sound and perform exactly like a japanese original.
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I built a Desktop Series version of this amp (single ended).
Do you have a schematic for this build?
:angel :angel
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I built a Desktop Series version of this amp (single ended).
Do you have a schematic for this build?
LC posted a layout in this thread:
http://www.el34world.com/Forum/index.php?topic=8494
and stated:
Schematic is the original Jubilee with an SE power amp.
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Thanks LooseChange for sharing that with us it looks like a real nice build.
I love your desktop versions and then you sharing your results with us, I learn something everytime you build a new one.
I also love the fact that everyone here are such active builders, sharing your results so we can learn. you fuel my passion for this hobby by reading about whats being done by other members here. Always something new.
Bill