kharp11 posts02-04-2018 9:34pmI realize this thread has a little bit of age, but, was wondering if anyone here still has a set of prints on the Usher 1.5 or 2.5 they'd be willing to send?
PM vvvinashhh he has them.
Cheers George
Usher R1.5 should I buy?
Hello all, I thought this is one forum where I should ask and take the approval of all the experienced souls here before I pull the trigger today or next week satday. The Question is should I buy the Usher R1.5 , is it as good as the press says or the reviews here or around the web suggests.As for speakers I have a Mission MX5 for now with Denon PMA1500AE /DCD1500AE/TU1500AE as amp CD and tuner with Chord cables. This is the cheapest power amp I can afford at the moment , that too class A till some watts. If anyone has any encounter with this amp please advise me. I listen to only RocknRoll and very little Jazz ( read Norah Jones , Diana Krall) buy it's always Queen and Ledzep , Floyd GnR, CCR,GFR,Lamb of God Korn , Blue Man Group, etc etc. I'm a SACD enthusiast,s o no vinyl in the mix. Love warm rich lush and not forward sounding gear. Please advise if the Usher is good enough as a power amp.
Showing 8 responses by georgehifi
Your Usher has a fet inputs at 61kohm loading with a fair amount of gain. I would suggest a low gain preamp like a Schiit Freya for $699, bonus is you can use it as straight passive, a tube, or a solid state (to suit your moods? maybe) and it has a trial period. http://schiit.com/products/freya Cheers George |
desalvo55I gave the circuit diagram to vvvinashhh above, on the condition he passes it on, email him and he’ll forward it to you. Or send me your email,, and I'll send it, with the bias pot circled in red and the emitter resistors in red, which need to be monitored with a dmm when adjusting the bias pot Cheers George |
But I don’t know how to set bias :( So I guess I’ll "probe" around, find a pot, and adjust till my hand starts burning?Say goodby to your amp! Seriously, please get a tech to do it, as you need to put dmm meter probes on the emitter resistors, and that is a hairy place to be, as it’s very confined. Cheers George |
I had the circuit, but it’s long gone now, but if you warm it up with the lid on for at least an hour, and if still not warm enough (use Pass palm test) Monitor the bias across the emitter resistors (yes they used them the same way as NP did, collectors drove the speakers) with a DMM and increase 10mV at a time till you get the right heatsink temp, both channels. And yes more cap uF the better on the power supply, but many small ones are better than big ones, as they can release their storage quicker and give you far better transient response. PS: Just found the circuit of the Usher 2.5 send a PM if you want it with your email address. Cheers George |
vvvinashhhI might also add the ones I've played around with, were under biased,, and needed to to be adjusted a bit higher to get the Class A bias of the Thresholds, "as Nelson palm detector adjustment", enough bias to keep the palms of you hand on a fully warmed up heatsink for at least 6 seconds, (bricklayer exempt from this test) Cheers George |
vvvinashhh Usher R1.5 and R2.5 were almost direct copies of the Threshold Stasis S200 and S300. I showed Nelson Pass the circuits of the Ushers, and the only difference was they had one extra gain stage transistor in them, which Nelson replied was what he would have done if he did a re-design of them. So your in good company as I owned an S300 mkII and it was a very nice smooth amp with plenty of grunt. Cheers George |