February meet recap

Doc B. · 1477

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Offline Doc B.

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on: February 06, 2017, 06:36:56 AM
Saturday's get together was a nice small one, with just seven of us in attendance. I have found over the years that those can be some of the best meets. I followed through with my promise to talk about system tuneup, though it was a pretty brief one. I showed the process of chucking up a cut-in-half Q-tip in a Dremel and using it with some metal polish to clean up tube pins, followed by some DeOxit, which should also be used on every RCA and XLR connection. Tube sockets get brushed with some cool tiny brushes I found on ebay, and treated with DeOxit. All pots and switches should be exercised to clean any schmutz off the contact surfaces. And finally, a thin coating of dielectric grease goes on the prongs of all power cords.

We did quite a bit of listening to the new speakers, the high point of which was some really nice vinyl selections that Josh brought.

At one point PJ was talking through some ideas with Aaron about his next project, which will use some TL-404s.

At the end of the meet I asked the gang to listen to a mix I have been working on, a capture by Jim Laurel from the show that Jacqui Naylor and Art Khu gave in us December. I was surprised to find that the song that had been sounding pretty good using Reaper and my PC laptop sounded really harsh and bright on the Mac Mini music server. This led to some quick sampling of different music players on the Mac. Suffice it to say that there were some striking differences. That was just the first step and I will be doing a lot more listening to the latest generation of players. I was surprised to find that iTunes sounded pretty darned good.

Next month we will be attending the Port Townsend Record Show on March 4th, so that will be our official March meeting. Apparently past shows have been quite successful with a good crowd and lots of vendors. We will have a table there and be demoing a phono rig and headphone amps. Admission is free, and vendor tables are reasonably priced.

http://ptrecordshow.com/

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline johnsonad

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Reply #1 on: February 07, 2017, 02:35:04 AM
As Dan said, it was a great time with a small group.  The speakers continue to improve and they image like nothing else I can remember listening to.  They sound great now and it sounds like the team still have a few tricks up their sleeves.  If you are in the area, stop by BH and give them a listen.

Dan's clean up talk was great and the q-tip and metal polish on the tube pins was new to me.  I use 0000 steel wool most of the time or a brass brush for the stubborn stuff.  Cleaning and polishing makes a surprising difference. 

PJ was a gracious help with my latest mod to the 300B amps based on what Xavier is doing on his latest build.  The plan is to put a pair of TL-404 XL's in the amp along with EXO-050's and switch between the OPT's.  The grounding is where I was getting confused and PJ saved the day!  More to follow once the transformers arrive.

The highlight for me was listening to different software with the same track in the same system.  I've done the same at home and settled on one that works for my system but it's interesting to hear the results in a different system.  Software shouldn't have that much difference in SQ but it does. There seem to be some new players and I'm planning on trying some of the latest to include Roon and see if it's time for an upgrade. 

These meeting are great and a big thank you to the BH team for hosting them :)


Aaron Johnson


Offline xcortes

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Reply #2 on: February 07, 2017, 06:16:38 AM
And the grounding saga continued throughout Sunday night as Aaron and I had a long discussion of the dangers of dc on the tl404s as pointed out by PJ in the meeting. I ended up having to understand how the "we negative rail" works and why it is important in an autoformer amp. Until I figured out that my amps do not return the autoformer ground to the cathode but to the ground instead, making the whole discussion pointless. But we learned a lot!

Xavier Cortes


Offline johnsonad

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Reply #3 on: February 07, 2017, 08:42:52 AM
We did learn a lot 😊

Aaron Johnson


Offline Paul Birkeland

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Reply #4 on: February 09, 2017, 07:27:38 AM
Until I figured out that my amps do not return the autoformer ground to the cathode but to the ground instead, making the whole discussion pointless. But we learned a lot!
Yeah, PJ is a bit of a master of pulling negative ground rails out of nowhere to make autoformers work properly. 

I can remember him being a little bit grumpy about the original SEX 2.0, as Doc B. insisted that the old Speco T-7010 sounded a bit better wired as an autoformer, and the unusual fixed bias configuration in that kit had to be implemented to allow that. 

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man