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Little Dot MKIII Tube Rolling
Apr 21, 2008 at 5:30 PM Post #647 of 3,408
Also CAHG - Chatham Electronics
 
Apr 21, 2008 at 5:47 PM Post #648 of 3,408
EDIT 4/27/08: Don't buy these for making adapters. Also, 6h30's cannot be adapted. A board mod is required.

For anyone looking to make some Bulldapters, I just ordered a bunch of these:

Vacuum Tube Socket Savers 9 Pin (10 pieces) - eBay (item 130215311246 end time Apr-21-08 16:51:30 PDT)

The guy sells these in 4’s or 10’s

I’ll post an update when they arrive. Looks like an easy one piece solution to make 9-pin adapters. I plan to use them to make two 6H30 adapters with a resistor in circuit, rather than replacing the one in the board.

I’ll go back and reread this thread about the resistor value and which pin is correct in installing the additional resistor, but if anyone would be so kind. A basic “how-to” would be most helpful. (with an adapter, the additional resistor will be in series…)

Thanks,

E

I have a pair of EH Golds begging to be installed
wink.gif
 
Apr 21, 2008 at 5:55 PM Post #649 of 3,408
Quote:

Originally Posted by ethebull /img/forum/go_quote.gif
For $2 a piece, I couldn't resist
biggrin.gif



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Glad you snagged them!! Looking forward to your impressions of them seeing as we have the same lot of Sylvania's...
Listening to music such as Eric Clapton's Unplugged and the clear "Fender" sound of Robert Cray's guitar work on his Definitive album I am prefering the Raytheons...There just seems to be more detail and air around the instruments and everything seems cleaner...And boy do they glow
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Apr 21, 2008 at 6:06 PM Post #650 of 3,408
Always fun to check out some highly regarded tubes. Especially when they cost $2 each
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I'll be surprised if I like them better than the Syl's, but you never know. It's their overall balance that I find so pleasing, so more of anything might be a negative (?) I'll post an impression in a week or so.
 
Apr 21, 2008 at 7:07 PM Post #651 of 3,408
Quote:

Originally Posted by ethebull /img/forum/go_quote.gif
FYI, here are some JAN Tube Designators:

CHS = Sylvania
CHY = Hytron/CBS
CRP = Raytheon
CTL = Tung Sol
CRC = RCA
CNU = National Union
CKR = Ken-Rad or (later) GE
CG = GE



Hey thanks. The gray plate Sylvania's I have are so close to the stock GE 5654s that came with the unit that they must have been made by the same manufacturer, so my guess would be GE made them all. Only difference I can spot is slightly different slots in the plates. Based on box age (again not an expert!) I would say the gray plate Sylvania's I have are 1950's, maybe 60's and the two with black plates and halo getters are 1970's.

I'm interested in other tubes too of course but also have my doubts about anything being better than the good Sylvanias! They have a nicely balanced sound but their selling point IMO is the amazing 3D soundstage as Penchum mentioned.
 
Apr 21, 2008 at 9:47 PM Post #652 of 3,408
Quote:

Originally Posted by dr dougie /img/forum/go_quote.gif
I'm interested in other tubes too of course but also have my doubts about anything being better than the good Sylvanias! They have a nicely balanced sound but their selling point IMO is the amazing 3D soundstage as Penchum mentioned.


I'm with you on all counts. They have fantastic soundstage. I said early on that I found it difficult to describe their sound - They have great _____ - fill in the blank, across the board.
 
Apr 22, 2008 at 1:10 AM Post #653 of 3,408
Quote:

Originally Posted by dr dougie /img/forum/go_quote.gif
Hey thanks. The gray plate Sylvania's I have are so close to the stock GE 5654s that came with the unit that they must have been made by the same manufacturer, so my guess would be GE made them all. Only difference I can spot is slightly different slots in the plates. Based on box age (again not an expert!) I would say the gray plate Sylvania's I have are 1950's, maybe 60's and the two with black plates and halo getters are 1970's.

I'm interested in other tubes too of course but also have my doubts about anything being better than the good Sylvanias! They have a nicely balanced sound but their selling point IMO is the amazing 3D soundstage as Penchum mentioned.


Quote:

Originally Posted by ethebull /img/forum/go_quote.gif
I'm with you on all counts. They have fantastic soundstage. I said early on that I found it difficult to describe their sound - They have great _____ - fill in the blank, across the board.


I'm still maturing the Sylvania's I got last week. So far, very impressive. Next week, I'll try to do a small comparison between those and the GB-5654's. That will be a very tough comparison for sure.
smily_headphones1.gif
For a day or two prior to the comparison, I'll switch back to a favorite fun tube like the 6Z and get used to that sound again. This will help my perceptions greatly.
smily_headphones1.gif


Does anyone know if DoA has posted the tube guide yet?
Thanks!
 
Apr 22, 2008 at 3:26 AM Post #654 of 3,408
dgbiker and webghost,

I've looked at your posts about installing resistors and switches to adapt the 6H30 power tubes. I don't see a direct board trace that leads to a particular pin or pins on the power tube. This has me thinking an adapter plug with resistor is not a workable option. Any thoughts?
 
Apr 22, 2008 at 7:49 AM Post #657 of 3,408
Quote:

Originally Posted by ethebull /img/forum/go_quote.gif
dgbiker and webghost,

I've looked at your posts about installing resistors and switches to adapt the 6H30 power tubes. I don't see a direct board trace that leads to a particular pin or pins on the power tube. This has me thinking an adapter plug with resistor is not a workable option. Any thoughts?


I'm not sure that an adapter will work. Looking at the pictures, it looks like the resistor is in parallel with a capacitor looking from the tube socket.
MKIIITubeSockets.jpg

So if you add 52Ω directly to the resistor (the "old" way) you get the impedance of that branch being:
Zeq=1/(1/(68Ω+52Ω)+jwC)=1/(1/120Ω+jwC)
With a tube adapter it would look like:
Zeq=52Ω+(1/(1/68Ω+jwC))
Not sure if that would hurt anything, but it doesn't seem safe.
 
Apr 22, 2008 at 12:25 PM Post #658 of 3,408
Quote:

Originally Posted by absolutlemur /img/forum/go_quote.gif
Matched pair of Amperex 5654 on the way
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Excellent! The Amperex 5654's are great tubes! Nuetral and balanced with no serious short comings. I still use them for a point of reference in judging others; one of my early favs. So now you have two choices: sit back and enjoy your great amp with some excellent upgraded driver tubes, or, jump on the looney train with the endless pursuit of the holy grail.

I think I'm about to jump off the train... soon... maybe....
 
Apr 22, 2008 at 12:42 PM Post #659 of 3,408
Quote:

Originally Posted by dgbiker1 /img/forum/go_quote.gif
I'm not sure that an adapter will work. Looking at the pictures, it looks like the resistor is in parallel with a capacitor looking from the tube socket.


Thanks dg, I could see by the board traces that my hopes for a plug solution were a long shot. This morning, David at LD confirmed this as well:

"Hello Erik,

Ah, if I understand what you are trying to do, adding a resistor to an adapter so that the resistor is in between the tube pin and the PCB socket will not give you the results you need to use the 6H30. Unfortunately the portion of the circuit we are talking about here is not set up in a way where such a simple and "clean" solution would work.

Best regards,
David"

Oh well. Radio shack here I come. Damn the voided warranty, those EH golds are too meaty to ignore.
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(sitting in my drawer, money already spent
wink.gif
)
 
Apr 22, 2008 at 1:11 PM Post #660 of 3,408
Quote:

Originally Posted by dan_can /img/forum/go_quote.gif
I don't think matched driver tubes are critical in Little Dot amps. All my unmatched pairs work just fine.


There are a few levels of reliability to consider when buying tubes.

First you have new current production, matched or un-matched
NOS - as is un-tested, tested but not matched, matched and tested
Used - as is un-tested, tested but not matched, matched and tested

Then you have to judge the seller and their rep
Dump all this in your risk calculator and factor in the cost...

I've bought some great un-tested cheap stuff, I've bought NOS matched and tested that I didn't care for, though they worked fine.

If you're like me (buying way more varieties of tubes than any reasonable person should) picking up a cheap dud is less iritating than spending big bucks on a so so tube. If you plan on buying just a few choice tubes and be done with it, buying matched at a premium price is safe and smart.
 
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