G600

Thank you. Which ones are critical ? Can I match only small bipolars, or power transistor need to be matched too ? Another one : matched sand goes in the same rail, or each rail has to be matched with the other ? Regarding your experience, do you think that onboard Dynahi must be biased to only 50mA ? My first board (the one that stops at 74mA with 500 Ohm) becomes hot, but the second one's left channel goes hotter. I think there's something wrong with that one.

Hello there. I started biasing my two boards (onboard version), and need help... PSUs are two 30V S22 with 160VA transformers, boards have lowered gain, red LEDs, ON MJE15030G and 15031G, every sand is from Mouser, no matching as I don't have tools for that. The first one : no offset from start, easy as a pie, but the bias can't go above 0.4V with the 681 Ohm resistor. I've changed for 500 Ohm but I can't go above 0.74V ! Still no offset by the way. What can be wrong with it ? The second one : nightmare. The left branch goes well to 0.75V (681 Ohm resistor too), and becomes incredibly hot, while the right channel stops at roughly 0.5V (and stays cold). Then I started tweaking the THAT340 pots, I could bring the bias close to correct at the right branch, and suddenly I heard something like an intermittent short, plus a bad smell from this right branch... I guess I'm good for a BJT sanity check, but what can explain the odd behaviour at first start ? Thanks.

I had them at home, and Mr Gilmore came with this : So looks like the difference is way out of reach...

I chose 5pF.

Thank you !

I have some fine (silly) questions for you gentlemen I'm at the point of first power on. I'm OK with the biasing method. What's the most efficient method, biasing with the pot or with shorting resistors ? Shorting resistor = 1K between I- and Gnd, and another between I+ and Gnd ? Pot to minimum setting = full clockwise ? Is there any need of a switch or a soft start between PS and Dynahi ? What if the source brigs a few mV of DC offset ? Thank you.

You have an email, then ! Thank you fellas.

Thank you AIve. May I ask where you found a PCB for a quad pot ?

Aive, What kind of pot are you using ? Have you built the amp with defaut gain (balanced gain of 42) ? Thanks.

Thank you ! Time to order the last parts and finish the boards.

That's pretty clear given the formula. My problem is the compensation cap value, without a scope I can't be sure of the frequency response, unless somebody helps me. I read 5pf is OK for a balanced gain of 11 (10k - 55k).

Dr Gilmore; Have you calculated the exact value I need for a balanced gain around 11 ? Thanks !

Thank you Dr. Gilmore. I'm trying orthos for now (LCD-2 = 50 Ohm / 91dB), so I think they'll take benefit from the Dynahi with lowered gain. I'll probably try HE-6 and / or K-1000 in the future, so this upcoming balanced Dynahi will be on duty. When I switch to dynamic headphones (or higher efficiency stuff), I'll build a dynalo (or dynamid) for sure, thanks for the tip !

Can somebody help me by confirming this ? I'm populating my boards right now, and still don't know if this way to obtain a balanced gain of 11 ( (50k/10k)+1 <-> 5+5+1) is OK, especially for the compensation capacitor. Unfortunately I don't have no scope and not much skills to guess this... More generally, is a balanced gain of 11x more friendly to run headphones between say 30-300 Ohm ? Best regards.

What would you recommand as the most versatile balanced gain ? 10x or 14x balanced ? What components to swap for that (especially the capacitor, to ensure proper frequency response) ? Thanks !

Pleaaaase fellas, that wasn't the thread's purpose... Not another HF-like thread (By the way Audeze's flagship stays the LCD-3, if you don't feel that way I guess it's just you...). Yes, and thank you all for that. So balance Dynahi (aka Dynamite) it will be. I'm nor starting the build right away, I have to fulfil my DAC a bit, and learn some about KG's beast, as I may be a lil' short on skills for it right now. It'll be quite an experience for me ! Thanks !

Thank you, that was just what I was looking for. The endless troll about who's right or not resurrecting/building orthos, is none of my business. It looks like the initial thought about a balanced Dynahi is definitely the way to go.

Yes, as long as you consider the LCD2 and 3 as real headphones ! My goal is to build a balanced beast, able to control them and bring them to their limits (in term of slam, control, etc... not SPL as I don't plan to become deaf that soon).

As I can't live without knowing ( ), I guess I've to build one...

The master mastering on the living room's table, really nice ! Nobody for an input about Audeze over the Dynalo family ?

I haven't heard of those gainclones before. They look nice !

In fact I'm using LCD-2 and LCD-3 is a probable upgrade. As said I've read many good things about B22 (and you said a good part of them in fact). But all the attention seems to go to the Dynalo family now. I'm pretty sure SS amp are the way to make those two Audeze stellar, and choosing DIY for fun and cost. If they can squeeze the extra juice from my LCD-2, please point me which one to go (and if I'm likely or not to fulfil it...). I'm just now paying attention to my source, as I'm building and tweaking a DDDAC1794. Thanks.

Hello guys. I'm new here, and want to thank you for welcoming me. After some months of tube trials, I'm thinking of SS to power my orthos. I would like to go balanced all the way, and I want your advices on which KG's amp to go. I've read brilliant things on the B22, but it seems surpassed by the Dynahi family (balanced Dynahi, Dynamite,...) -correct me if I'm wrong-. So what's your experience with those orthos ? Which amp must I build ? I've read the Balanced Dynahi build thread, there are some useful tips and help there. As I'm not deep into electronics, and a lightweight DIYer, is it an utopia to build one ? My very best regards from old Europe.