My 1st tube preamp

happyrabbit · « **on:** 15 Feb 2012, 01:26 pm »

This will be my 1st tube product.... Go Big or Go Home

Custom built by Jeffrey Jackson. I should get it next week...

I am a tube virgin so be gentle !

Dwight

Old timer · « **Reply #1 on:** 15 Feb 2012, 02:06 pm »

Just curious, what did you have to pay for your custom preamp?

thunderbrick · « **Reply #2 on:** 15 Feb 2012, 02:28 pm »

bregez · « **Reply #3 on:** 15 Feb 2012, 03:45 pm »

Seems to have a lot of wood in the chassis. Mounting tube sockets on wood is not very ideal, especially rectifier tubes that will run hot.

ltr317 · « **Reply #4 on:** 15 Feb 2012, 05:13 pm »

Wow, that's a lot of chokes and transformers for a preamp. The unit looks more like an integrated amp because of its apparent complexity.

JoshK · « **Reply #5 on:** 15 Feb 2012, 06:56 pm »

That is going to be one badass preamp! I think you are going to be very pleasantly surprised. I have a 45 based preamp and its the best preamp I've heard. Jeffrey (whom I consider a friend) likes the 71a for a preamp tube even more and nickel chokes are the bomb.

JoshK · « **Reply #6 on:** 15 Feb 2012, 07:03 pm »

Quote from: bregez on 15 Feb 2012, 03:45 pm

Seems to have a lot of wood in the chassis. Mounting tube sockets on wood is not very ideal, especially rectifier tubes that will run hot.

I don't think I agree. Ceramic sockets are extremely good insulators, meaning very little if any heat will be transferred from the pins to the wood. If you mean just via close proximity, well I'd still argue, it won't be hot enough to be a problem.

bregez · « **Reply #7 on:** 15 Feb 2012, 08:47 pm »

Quote from: JoshK on 15 Feb 2012, 07:03 pm

I don't think I agree. Ceramic sockets are extremely good insulators, meaning very little if any heat will be transferred from the pins to the wood. If you mean just via close proximity, well I'd still argue, it won't be hot enough to be a problem.

I agree that ceramic is a good insulator, the pins coming out of the bottom may run around 200F. I mentioned it more as a precaution rather than a fire hazard. My point is if you are going to do that much work on a preamp why not just mount everything on a sheet of aluminum. Save the wood for cosmetic purposes.
Another advantage to using aluminum would be improved EMI shielding that is extremely important in preamps.

Syrah · « **Reply #8 on:** 15 Feb 2012, 10:01 pm »

This will definitely be a fire hazard and Dwight should send it to me as soon as he gets it, you know, for his own safety. You're welcome Dwight.

That looks awesome.

happyrabbit · « **Reply #9 on:** 15 Feb 2012, 11:02 pm »

couple thoughts -

tube life ~20,000 hours (a couple sets of tubes will last me a life time)

magnetic attenuator -> DHT (71A) -> magnetic coupled output (no caps or resistors in the signal path)

the wood is used to isolate and maybe tone control ?? not sure...

the volume control is supplied by Bent Audio... aka Tap-X (a very nice passive)

this preamp is a Tap-X with a buffered output stage. a very nice outout stage...

Syrah - I will keep u updated on my 'fire hazard'

Dwight

dwight

Quiet Earth · « **Reply #10 on:** 15 Feb 2012, 11:44 pm »

That's a very cool looking pre. Has all the right stuff.

Love to see a shot of the front when you have time.

Enjoy.......

JakeJ · « **Reply #11 on:** 16 Feb 2012, 02:56 am »

I'm with Josh, this is going to be one sweet preamp, especially for your initial dip into tubes. This gonna be driving the Magus MA-200 into the Selah Tre Supremo Minis? Looking forward to hear your feedback on the sound.

And welcome to the circle.

Jake

happyrabbit · « **Reply #12 on:** 16 Feb 2012, 04:59 am »

I traded the Selah's for a pair of Rio's from Green Mountain Audio. I like the Magnus MA-200. A Class A Amp designed by Canary.

mal · « **Reply #13 on:** 16 Feb 2012, 11:32 am »

That is an astoundingly gorgeous piece of kit. I'm having a severe lust problem.

mhconley · « **Reply #14 on:** 16 Feb 2012, 01:02 pm »

Quote from: mal on 16 Feb 2012, 11:32 am

That is an astoundingly gorgeous piece of kit. I'm having a severe lust problem.

+1

I have never heard of Jeffrey Jackson so I Googled him. His work looks inspired. Amazing stuff...

Martin

poseidonsvoice · « **Reply #15 on:** 16 Feb 2012, 01:31 pm »

I'm with JoshK. You are going to have an out of body experience with this preamp.

Have fun, looks well designed.

Anand.

jtwrace · « **Reply #16 on:** 16 Feb 2012, 01:41 pm »

Quote from: Old timer on 15 Feb 2012, 02:06 pm

Just curious, what did you have to pay for your custom preamp?

Jeffrey Jackson isn't cheap. I had inquired before purchasing my TRL Dude ($4k) and he was north of $10k and it's not hard to do with his products.

JoshK · « **Reply #17 on:** 16 Feb 2012, 02:01 pm »

Quote from: jtwrace on 16 Feb 2012, 01:41 pm

Jeffrey Jackson isn't cheap. I had inquired before purchasing my TRL Dude ($4k) and he was north of $10k and it's not hard to do with his products.

Nope, but unlike some high price stuff, his design philosophy is to make heirloom pieces, not disposable gear you will flip on a'gon in a couple of years. He uses really expensive parts. Price out some of those nickel chokes if you want some more sticker shock. Point to any other tube equipment out there that uses nickel chokes/iron. I can think of Gordon Rankin's Wavelength audio which has similar price tags. I can think of no others.

I wouldn't be surprised if the raw parts cost is north of the retail price of the Dude.

jtwrace · « **Reply #18 on:** 16 Feb 2012, 03:38 pm »

Quote from: JoshK on 16 Feb 2012, 02:01 pm

Nope, but unlike some high price stuff, his design philosophy is to make heirloom pieces, not disposable gear you will flip on a'gon in a couple of years. He uses really expensive parts. Price out some of those nickel chokes if you want some more sticker shock. Point to any other tube equipment out there that uses nickel chokes/iron. I can think of Gordon Rankin's Wavelength audio which has similar price tags. I can think of no others.

I wouldn't be surprised if the raw parts cost is north of the retail price of the Dude.

Right. I didn't say I disagree with anything that he does...I've also owned the Wavelength Crimson too.

Ericus Rex · « **Reply #19 on:** 16 Feb 2012, 04:24 pm »

HOLY MOLY!!!!!!

http://www.jeffreywjackson.com/Eimac75tl.htm