6550's replacing 1614's in a Ranger

[W3UTD]

Looking at the prices for 6550's ... 

So ...anyone have any experiences with the Russian tubes, Svetlana, Sovtek etc.  Or the ones imported for guitar amps?

I'm not sure I'd go with a Chinese tube though.

[k4kyv]

Would 6550's give you any more audio than the original 1614's? Are you using the stock modulation transformer? The peak audio voltage output from the modulator is almost entirely a function of the DC plate voltage and modulation transformer turns ratio, and has little to do with the tube type, assuming the latter is operated within its ratings and has adequate drive to the grids.

[N2DTS]

What is the difference, I dont have books with me at work...

I have a bunch of 6ca7's and 6550's I got at a fest some time ago I got no use for.
I have a bunch of new KT88's and KT90's from Eastern Europe, (not the ussr) that I would use instead.

Any of the evil empire tubes I tried had the bases come unglued and the plate caps are metric or something...

Brett

[W3UTD]

so how is it that every Ranger "mod" I have read suggests replacing the 1614's with 6550's, even the mods that are basic ones?

[AB2EZ]

Don

How about the transconductance difference?

According to the tube specifications, the 6550 has twice the transconductance of a 1614. I.e. the 6550 is equivalent to two (2) 1614's in parallel.

As a result, you can get the current swing you want with half the grid voltage swing... and you will not have to drive the 6550's as far into AB2 (from AB1).

For some applications (e.g. running the Ranger with reduced voltage on the plate of the 6146 to produce reduced ouput power), the modulator will definitely remain in AB1.

I'm happy with the Hytron / Tungsol (Russian) 6550 tubes I have been using in my Ranger for several years.

Best regards
Stu

[W2PFY]

I don't know what the pep of a stock ranger is but I put a pair 6550's in place of the 1614's and it easily made 170 watts pep. This ranger had the phase splitter rather than the driver transformer and also had solid state HV & LV in place.

These were Russian tubes.

[W3NP]

so how is it that every Ranger "mod" I have read suggests replacing the 1614's with 6550's, even the mods that are basic ones?

I switched to 6550's because the higher plate voltage that is present after solid stating the rectifiers exceeds the specs for all of the 6L6 variants.

[WD5JKO]

I switched to 6550's because the higher plate voltage that is present after solid stating the rectifiers exceeds the specs for all of the 6L6 variants.

   Here is one more variant, the SUPER 6BG6GA, a 6L6GC (35W PD) with a plate cap (700V EP) and 6BG6 base diagram, brand new NOS for $8 each:

http://www.vacuumtubes.com/6BG6.html

http://www.diyaudio.com/forums/tubes-valves/102802-6bg6-6l6gc-top-cap-cheap.html

these are not the same as the older 6BG6's...

These are from Mike, WB0SND's Epay store.....

YMMV,

Jim
WD5JKO

[ke7trp]

On my slightly modified ranger including Solid state supplies, I found little difference.

I tried a host of 6l6 format tubes:

Glass 6l6
Metal Mil spec 6l6
6550s
Various 1614s


I even tried the 8417. Always a favorite of mine.

In the end, I went back to the 1614 metal tubes.  They seemed to sound fine and work well.  I did all of this because I was trying to get to 100% mod which rangers wont do.  Mine, Is very happy to load up around 60 to 65 watts. It does not care to load much lower.  The PEP is around 150 to 160.  Sure, It sounds great but I was really trying to get that PEP up to 100% which would require over 200 watts.  Never even came close. 

I did find that the Amperex 6146 was clearly the hottest of the brands I tried.  RCA, GE, and Japanese brands. If you find one at a hamfest or junk box, Set it aside.

I do not know why people like to use the 6550.  I understand in theory but in use, I just did not see a huge benifit of using these now expensive tubes.

Clark

[The Slab Bacon]

just my $.02 worth:

6550s are prety kool bottles. I have done several rangers with them at the request of the owners.

 They were designed for class A or AB1 audio service and do not need to be pushed to the point of drawing grid current (AB2) to make some power. All that you have to do is tickle the grids with a little voltage and they will make tons of audio. This makes them especially well suited for use with phase inverter drivers instead of using the sometimes troublesome OEM driver transformers. Just tickle them with a little audio and away they go! !

Some of he imported ones are pretty reasonably priced (compared to what you pay for a Ranger) and all are good enough for speech audio.

It really boiles down to what you want to do with YOUR ranger. If you plan to run it barefoot as a solo transmitter, you want ALL the audio you can get. But, if you plan to use it as an exciter for a leanyour amplifier or a big-assed afterburner transmitter, it is a very different game. If you want to run it as a reduced power exciter (10-20w) then it is all a mute point as anything will make enough audio to modulate it at that power lever.

The Timtron is well known for his "turbo Ranger" mod that runs the final on the lowered B+ and the modders on the HV for extreeme audio peaks.

Just my $.02 worth

                                                              The Slab Bacon