Paul:

Tubes are actually as cheap or cheaper than they were in the 1950s, adjusted for inflation. Most are either made in former eastern bloc countries or in China. The quality of the Russian tubes is excellent, as they used tubes in their military equipment until recently, maybe even still do. One potential problem is that there are fewer tube types being manufactured now. It has settled down to the most common power and preamp ones being in abundant supply, and inexpensive. If you buy a used or 'vintage' tubed product, it is good to first look at what kinds of tubes are installed, and see if they are still being made. Stupidly, there are a couple of current amplifier manufacturers that buy up a good stock of obsolete tubes and design their new amps around them. Then you have to purchase any replacement tubes from them at whatever price they ask. Not a good way to treat customers.

SH:

When you looked at the ST70 mod I linked were those tubes one of the abundant and cheap types? Overall would you consider it worthwhile for me to pursue this avenue on my ST70? At $250 for the kit it seems pretty reasonable pricewise, and it did get a few good reviews, FWIW.

Lena, you say that you are going to become a display cabaretionist? What cabaret are you going to work at? Are old chums allowed to come to the cabaret?

Dear Paul….you made me fall off my chair. (and not very gracefully I'll have to practice before the 'cabaret) Best laugh I’ve had in front of the computer all day!
You see I have this vocabulary in my head. But I tend towards pronouncing things phonetically (people go huh?) and never learned to spell. Spell check just doesn’t know how to take me …..keeps telling me…. I am not worthy of suggestions! So after two tries…if I’m even in the mood to use spell check. I give up and think ….close enough.

I am always switching out words which pop into my head which I may have (or not) just invented for the occasion to something shorter or easier for spell check to discover. (Discover ….perfect example I typed DIS CYP ER and spell check just offered me the other choice). I do have vocabulary, yet…access is denied.

For example if I wanted to say super­calli­fragilistic­expiali­docious"., I always have to settle for plain old ‘super’. (wow, I just found the spelling for that one on the Mary Poppins web site).

The output tubes look to be the standard EL-34 types that are widely available and cheap. The 6GH8A input tube is still available, but I don't think they are being made currently. The rectifier tube is probably the same 5AR4, and that is also available, being made in Russia. If you decide to go with it, I would buy some replacements to last you for a few years. Maybe 4 or 5 more sets. Otherwise, I see no reason not to go for it.



[This message has been edited by soundhound (edited January 16, 2003).]

Lovely Lena, I'm glad to have brighened you day.

Soundhound, good to hear that tubes for the Dyna are reasonable priced. I was mostly thinking about retubing really expensive high-end stuff like top-of-the-line models from C-J, ARC, Manley and other tube power amps that use mulitple output tubes and for best result require tube matching.

Paul

Paul:

You jogged my memory about an important issue: When purchasing output tubes, it is VERY important to buy matched sets. If you don't, one tube may glow cherry red and the other be normal (not to mention the mis-matched audio between the tubes) when the correct bias is set unless the amp has provisions for setting the bias independently for each tube. The Dynaco ST-70 has just one bias adjustment for both tubes, so they must be a matched set.

[This message has been edited by soundhound (edited January 18, 2003).]

i have a st70. the 250 kit price sounds really good. i got mine cheap...but i had to replace...everything. got me to about 450 - 500 at the end ... and i still need to get the chassis dipped. blew my regulator tube last week ... i think while i was in the mid-east...my ex-girl friend tried to make it work.
i really like the jolida's...very elegant looking for the same money...integrated's, too. haven't keep up with much else there. the carey's are awesome...and the boogie amps....but i can't ...spend that kinda money ..even on groove tubes. where did i put that bad tube?
the joolidas (again, he says) put out some nice power and are very flat for a tube system. i love my ARC! it was the center for the system...now, a nice warm stage for the table...a music hall..nothing fancy (the cartridge is EVERYthing...and a platter that spins round at the rite speed..n, an arm that's made right. the ARC only uses one output tube per side for final gain. it's got a lotta gain, too! quite a few volts before ya blow your speakers up....save money nd get the ST-70. there's a simple mod for it..i down-loaded the schematics from somewhere, with the simple mod in it...the kit may already have it. it's just a lifting of 2 10 ohm resistors...at the input, i believe...need to get the drawings for that.

"...in a class A/B solid state output stage..."...SLL
true, but most of the decent silicon amps go 10 or 15 watts in class A and shift to A/B past that. gets ya thru the ruff times, one might say. i think my overture gets 15 mpg before shifting gears. my harley gets a little better than that. until they finally got that part right...they sounded like early digital 44/16. (what is happening to my ears..why do they hurt?) my ARC has more presence than the 950...but the 950 sparkles more ...in a lotta areas. there's some tube and SS mic pre-amps being made that have settings for that. set for sparkle and they throw in a little, subtle e.que-ing. gives a 'carver' holy-field to it that wraps you in more. don't tell anyone...i set up CNN's units for use in the field...only one other engineer knows that i changed about 16 channels to..'sparkle'...haha...they're gonna be using em for the iowa/new hamp thing and then the dem/repub conventions soon....hahahaha.! hey, how do you get the faces on different parts of the page?