Dennis Had Inspire Amps

[Comzee]

Originally Posted by bearcity

I am greatly appreciative of Staitwire and Analog Addict, and any of Dennis’ other protégés over the years, for doing what they can to understand and further the craft as best they can. I can tell you all hear though, we are all mere novices in the presence of a true master.

Agree for sure, I haven't the faintest clue about this stuff.
Just trying to offer some advice to pechel what helped me.

I think for my specific issue, it has something to do with a Lynx PCIe clocker which resides within my PC, which has a noisy switched power supply. It interactions oddly with my DH amps. My DH amps in any other chain don't have hum. Either way it's a non issue for me because I fixed it with that ground bridge.

[oldominion]

Originally Posted by pechelman

You noted stability for grounding, and I'm wondering if there is an issue with stability here since I did have brand new electroharmonix 6SN7 tubes that caused an incredibly loud feedback hum as they powered on. Could there be something funny going on with my amp? It doesnt seem to match your description of being quiet with its matching inspire amp. I sent Dennis an email a few days ago now with no response. Perhaps you could mention this to him? He also has my phone number. My user name matches my email address and includes my actual name.

-Phil

Just for the record, Dennis's 3.1 Preamp and Universal FireBottle SET are the best sounding components I've ever had in my system, and this from someone who's been in this hobby for decades.

That said, I'm on record in these pages that I've also had 60 cycle hum and microphony with my 3.1 preamp. Right now I have two Sophia blue 6sn7's and a Sylvania 6sn7 in the driver stage...I still have hum but microphony has lessened.

The hum is not specific to one input, i.e., it's not the phono preamp; hum occurs in my digital input as well.

Additionally, I, too, have experienced the STARTLINGLY LOUD screech from my preamp upon power up. It's happened at least five times. It's not just a little loud but, IMO, dangerously loud, capable of blowing something. No question. Has nothing to do with where the vol pot is set. Has happened with numerous different 6sn7's and rectifiers.

It does seem to me that the preamp, under certain unknown conditions, might have grounding issues that could be clarified or addressed by Straitwire that would help from a consumer standpoint.

[bwilson51]

Originally Posted by oldominion

Just for the record, Dennis's 3.1 Preamp and Universal FireBottle SET are the best sounding components I've ever had in my system, and this from someone who's been in this hobby for decades.

That said, I'm on record in these pages that I've also had 60 cycle hum and microphony with my 3.1 preamp. Right now I have two Sophia blue 6sn7's and a Sylvania 6sn7 in the driver stage...I still have hum but microphony has lessened.

The hum is not specific to one input, i.e., it's not the phono preamp; hum occurs in my digital input as well.

Additionally, I, too, have experienced the STARTLINGLY LOUD screech from my preamp upon power up. It's happened at least five times. It's not just a little loud but, IMO, dangerously loud, capable of blowing something. No question. Has nothing to do with where the vol pot is set. Has happened with numerous different 6sn7's and rectifiers.

It does seem to me that the preamp, under certain unknown conditions, might have grounding issues that could be clarified or addressed by Straitwire that would help from a consumer standpoint.

Are you powering up your preamp and waiting a minute or two before turning on your power amp.

[x3workshop]

^^^^ This is exactly what needs to be done. I had a similar problem with my LP-27a.

Dennis's answer was: "The hum is emanating from some of the 27 or 56 tubes as they bias up. The solution is to turn on the LP-27a a few minutes before turning on the amplifier. Or as I do I leave my LP-27a on 24/7. Not all of the 27 or 56 tubes act this way when warming up. The hum or noise into your Inspire amplifier will not harm the amp in any way. I build the Inspire stuff to play into a short if need be."

[oldominion]

Okay, great. Good to know. I guess it's my opinion that it would've been good to know from the start, as one who purchased both preamp and amp at the same time!

Does anyone else leave their tube gear on 24/7? Just curious.

[bwilson51]

I am sure some people leave their tube gear on 24/7 ,I power on my tube equipment the preamp first I wait a couple of minutes and then power up my power amp, I then wait and power up my sources and then I give everything about 15-20 mins before I sit down to listen.Seems to me leaving tube gear on 24/7 shorten the life of the tubes and if something fails could lead to real trouble.

[bearcity]

Originally Posted by oldominion

Does anyone else leave their tube gear on 24/7? Just curious.

Office: lp3a > custom Universal: 24/5. Turned off over the weekend.

Home: lp27a > PSE or 6V6er or both: usually leave lp27a on 24/7. Amps on during listening.

Never an issue except with 6k6s in the PSE. Wrong tube. Went nuclear while away. Blown fuse and stinky. Dennis helped me get her runnin again.

[Bombadil]

Originally Posted by bwilson51

I am sure some people leave their tube gear on 24/7 ,I power on my tube equipment the preamp first I wait a couple of minutes and then power up my power amp, I then wait and power up my sources and then I give everything about 15-20 mins before I sit down to listen.

This is what I do too.

[Cdrdel]

I must be lucky, not having microphony issues in my LP 3.1 and Universal setup (in Brooklyn Home). The same goes for my LP 27 and Triode SET amp (Upstate). I do plug in my amps and preamps into either an AVA Humbuster or Emotiva AC line conditioner. I think this may help a bit to clean up Con Ed's dirty power.

I do get a slight bit of 60 Hz hum, with an ear close to the speakers, 89 SPL GR Research DIY Studio Monitors and Jeff Bagby's (RIP) 95 SPL Fusion 8's. I had a JAN Ratheon 5U4 in the Universal Amp that was causing noticeable hum from my nearfield listening position. I replaced it with a NOS Dynaco labeled 5AR4, much-reduced hum. Also, I have had great results with a 5AW4 CBS Hytron (an underappreciated tube IMO). This is currently powering up Dynaco 6CA7's, really loving this combo; I'm using an RCA 6SL7 as the driver tube. Very lucky to have scored the Dynaco tubes out of a gifted ST-70. Tubes tested good and sound very good-now I see what all the fuss is with NOS Power tubes.

In the LP 3.1 not had any microphony with both Westinghouse/GE branded 6SN7's. Currently really enjoying the Westinghouse tubes buffered by Sylvania a 6BX7. The rectifier is RCA 5Y3.

I do not keep my amps on 24/7. I want my NOS tubes to last a long as possible!

[x3workshop]

I see no reason to leave my tube gear on 24/7 unless I'm listening 24/7. That said, I do leave them on for 10-12 hours a day.