rsint Posted February 15, 2019 Share Posted February 15, 2019 (edited) Edited February 15, 2019 by rsint Quote Link to comment Share on other sites More sharing options...
attackbass Posted February 15, 2019 Share Posted February 15, 2019 LOL! Maybe this stuff is hard to get in the states. I wonder how the used prices of Hellborg stuff will be effected after the Thomann blowout. I never intend on selling my rig now, it's such a cool rig I imagine I'll have it well into my old age. I just took delivery of my new Hellborg power amp, so I now have two and I can confirm that the power amps do impart a harmonic colouration to the sound. It's a shame you can't tap the output transformer with a DI. Quote Link to comment Share on other sites More sharing options...
three Posted February 15, 2019 Share Posted February 15, 2019 hahaha, I sold my first Hellborg power amp for £150 because of the harmonic colouration! Hmmm...not the most wise of decisions! 1 2 Quote Link to comment Share on other sites More sharing options...
Bigwan Posted February 15, 2019 Share Posted February 15, 2019 44 minutes ago, attackbass said: I just took delivery of my new Hellborg power amp, so I now have two and I can confirm that the power amps do impart a harmonic colouration to the sound. It's a shame you can't tap the output transformer with a DI. Not helping my GAS... I'm not even playing live at the minute and unlikely to be any time soon, but I STILL want in on this... Quote Link to comment Share on other sites More sharing options...
Owen Posted February 21, 2019 Share Posted February 21, 2019 It looks like the preamps have finished. Seeing as this thread is all about lurve for preamps chock full of transformers (apparently) has any one got any experience with an API Tranzformer LX? http://www.apiaudio.com/product.php?id=143 Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted February 21, 2019 Share Posted February 21, 2019 28 minutes ago, owen said: It looks like the preamps have finished. Seeing as this thread is all about lurve for preamps chock full of transformers (apparently) has any one got any experience with an API Tranzformer LX? http://www.apiaudio.com/product.php?id=143 +1 on that question RE the hellborg pre amp - while it is exceptional as far as I can tell it isn’t based on a Neve or API circuit but a high end pre stage based on a different preamp design based around the input stage IC . Also if I can read a schematic correctly the input stage transformer is bypassed when using a quarter inch jack lead in..., Quote Link to comment Share on other sites More sharing options...
Hellzero Posted February 22, 2019 Share Posted February 22, 2019 The input transformer is for the XLR as it's a combo input. You can read a schematic the right way. 😁 1 Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted February 22, 2019 Share Posted February 22, 2019 55 minutes ago, Hellzero said: The input transformer is for the XLR as it's a combo input. You can read a schematic the right way. 😁 That’s good to know , there’s videos about of Jonas talking about the input transformers ... I wondered if I were going mad. I ended up using it without the eq most the time, I have one of those plans that one day I will get round to where I DIY something similar Quote Link to comment Share on other sites More sharing options...
Hellzero Posted February 22, 2019 Share Posted February 22, 2019 I'm doing the same as you : no EQ. Quote Link to comment Share on other sites More sharing options...
three Posted February 23, 2019 Share Posted February 23, 2019 15 hours ago, LukeFRC said: That’s good to know , there’s videos about of Jonas talking about the input transformers ... I wondered if I were going mad. I ended up using it without the eq most the time, I have one of those plans that one day I will get round to where I DIY something similar This is really interesting, and something of which I wasn’t aware. I use the jack input and the very powerful EQ fairly extensively. This has me thinking. Would it be possible/useful to use a Pre/DI (Millennia, Avalon et cetera in pre eq mode and take a balanced line into the Hellborg pre - nice to see what extra the input transformer might provide (the jack alone is wonderful) - maybe a nice idea for passive/vintage basses? Quote Link to comment Share on other sites More sharing options...
Hellzero Posted February 23, 2019 Share Posted February 23, 2019 That could be an idea... Quote Link to comment Share on other sites More sharing options...
rsint Posted February 23, 2019 Share Posted February 23, 2019 But in this schematic the transformer comes after the join of xlr en cinch input? I would read that as being used for either. Quote Link to comment Share on other sites More sharing options...
three Posted February 23, 2019 Share Posted February 23, 2019 Thanks Hellzero and rsint - I'm afraid that I don't posses even the most perfunctory skills in reading schematics. I'm eager to see if the jack/xlr provide different routes (either vie the input transformer of not) - I'm not sure if there's a definitive answer to this one without taking the unit apart... given the above, something for which I certainly don't have the skills! Any further views very welcome... I suppose I could just try it with the balanced line from a Millennia TD-1 Quote Link to comment Share on other sites More sharing options...
Hellzero Posted February 23, 2019 Share Posted February 23, 2019 This is what the schematic is saying, but as it's a simplified version, I would trust it. Why, simply because of the input impedance matching. Let me take a look at the manual again... Quote Link to comment Share on other sites More sharing options...
Hellzero Posted February 23, 2019 Share Posted February 23, 2019 Super, the unbalanced jack goes into a buffer/impedance adapter and then to the transformer. This preamp is really well thought. Here is what the manual says : "The centre piece of the “Hellborg Amp System” is the Preamp. The input is a combined ¼”/XLR jack providing both low (XLR) and high (¼”) impedance. The input jack is followed by an input transformer. This imparts galvanic signal isolation and the sweetness for which good transformers are known." No need for your Millennia TD-1, you can give it to me. Don't worry, I'll pay the shipping fee. 🤣 1 1 Quote Link to comment Share on other sites More sharing options...
itu Posted February 23, 2019 Author Share Posted February 23, 2019 According to the schema, the 1/4" input has a buffer (most likely hi-Z to lo-Z) before going in to the input transformer. This makes sense, as this X-former obviously is a lo-Z unit. I would see no reason to use a DI-box in front of it. I would point out, that certain bass preamps, and I mean those in the bass itself, could drive the lo-Z input. This would be possible with an XLR-XLR, or a 1/4"-XLR (1+3 to ground and 2 to hot) cable. Wal, Vigier... probably most basses with active output. Would be worth trying. I see no reason to use two buffers before the X-former. Quote Link to comment Share on other sites More sharing options...
three Posted February 23, 2019 Share Posted February 23, 2019 Excellent, thank you all – I’d read the manual to but didn’t pick up the sentence relating to the combined input’s positioning. As you suggest then, no need to use a further DI for the jack. I thought it sounded pretty tremendous anyway – we are always looking for marginal gains! Thanks Hellzero for your very kind offer in relation to the Millennia, though I may just find another use for it! Thanks again all Quote Link to comment Share on other sites More sharing options...
LukeFRC Posted February 23, 2019 Share Posted February 23, 2019 1 hour ago, Hellzero said: Super, the unbalanced jack goes into a buffer/impedance adapter and then to the transformer. This preamp is really well thought. Here is what the manual says : "The centre piece of the “Hellborg Amp System” is the Preamp. The input is a combined ¼”/XLR jack providing both low (XLR) and high (¼”) impedance. The input jack is followed by an input transformer. This imparts galvanic signal isolation and the sweetness for which good transformers are known." No need for your Millennia TD-1, you can give it to me. Don't worry, I'll pay the shipping fee. 🤣 I don’t have it on me at the moment but the simplified schematic doesn’t match what the actual schematic for the preamp seems to be saying... I’ll check it again tomorrow when I can dig it out Quote Link to comment Share on other sites More sharing options...
Hellzero Posted February 23, 2019 Share Posted February 23, 2019 @LukeFRC : If you have the complete schematic of the Hellborg preamp, please share it. Here are the guts of if : Quote Link to comment Share on other sites More sharing options...
three Posted February 23, 2019 Share Posted February 23, 2019 (edited) Not had the lid off mine, but you can start to see where some of the money has gone Edited February 23, 2019 by three spelling Quote Link to comment Share on other sites More sharing options...
rsint Posted February 23, 2019 Share Posted February 23, 2019 2 hours ago, LukeFRC said: I don’t have it on me at the moment but the simplified schematic doesn’t match what the actual schematic for the preamp seems to be saying... I’ll check it again tomorrow when I can dig it out The only other schematics I have seen are the one for the poweramp, and the one for the lights in the preamp. btw.....if you were wondering why that stereo amp weighs 21 kilo’s that’s a lot of heavy metal 😎 Quote Link to comment Share on other sites More sharing options...
itu Posted February 23, 2019 Author Share Posted February 23, 2019 I can not see the op amp types but all resistors are metal film ones (best choice noise wise). It would be nice to see, what is inside those steel boxes (shields) in the preamp. The other has to be the power transformer (leftmost) but how about the other? Those toroidal transformers in the power amp are serious. Quote Link to comment Share on other sites More sharing options...
rsint Posted February 23, 2019 Share Posted February 23, 2019 1 minute ago, itu said: I can not see the op amp types but all resistors are metal film ones (best choice noise wise). It would be nice to see, what is inside those steel boxes (shields) in the preamp. The other has to be the power transformer (leftmost) but how about the other? Those toroidal transformers in the power amp are serious. I think the on the left is the input transformer, then there’s the coil based eq section in the middle one and the one on the right is the power transformer....upper left is the d.i. Output transformer. yeah those trannies in the p.a. are serious.....ly heavy. 😬 1 Quote Link to comment Share on other sites More sharing options...
Hellzero Posted February 23, 2019 Share Posted February 23, 2019 In the preamp, the unknown opamp is the buffer/adapter for the high impedance jack input that goes to the rectangular transformer (relay switching for direct coupling of the balanced XLR). The middle circular thing is the coil for the EQ (multiple outputs). The right one is the oversized toroidal power transformer. The upper left rectangular plastic thing is the DI transformer. All metal coverings look like Mu-metal... So a no compromise conception indeed. Quote Link to comment Share on other sites More sharing options...
rsint Posted February 23, 2019 Share Posted February 23, 2019 Some of the opamps are TI ne5532p Quote Link to comment Share on other sites More sharing options...
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