6gw8 replacement?

[sebtones]

hi all, i have recently bought an old aussie made amp that needs a pair of 6gw8(ecl86) tubes to be up and running. its been fully restored and converted from PA to guitar use but the seller kept the tubes because theyre so hard to come by...basically i was wondering if there are other tubes that will work in their place? theres some 6gv8 valves available nearby or maybe el84's? nah, that'd be too easy!! any help appreciated, thanks for looking, seb.

[black_labb]

6gw8's are a triode and power pentode in one valve. you could maybe aproximate it with 1/2 a 12ax7 for the triode and a el84 for the pentode if you dont mind an extra tube... theres also 6bm8's, but their not that cheap an option.

evatco also has some nos and used 6gw8's http://www.evatco.com.au/webcat1p3.htm

would be easier than trying to rewire the amp for something else.

[sebtones]

thanks for that, ive tried evatco and theyre trying to get some in from o/s. ive called a heap of places but no joy anywhere, hence the search for an equivalent.

[6267]

6F3P is the russian 6BM8 equivalent, probably available in bulk cheap...may require some redesign, but plenty available.

[andrew_k]

I was going to offer to lend you some 6BM8, but they have a different pinout and lower voltage ratings.

Here are some local 6GW8 on fleaBay - http://cgi.ebay.com.au/2-X-PHILIPS-M...3A1|240%3A1318

[sebtones]

thanks andrew, ive actually already got a bid on those, fingers crossed! cant wait to get the little beast up and running...

[tubeswell]

FYI there's a couple for sale on the kiwi flea bay at the mo'

http://www.trademe.co.nz/Electronics...-210846398.htm

[sebtones]

thanks for the help guys, i actually just received 10(mix of aussie made mullard, miniwatt, awa, and radiotron)6gw8's from ebay. the conversion is actually not complete, it still has the original PA output transformer. i won some speaker line transformers on ebay last night(thank god for ebay!) and once i get them worked out should have a nice little amp. i actually tried it with the new valves last night and was pleasantly surprised by the warm tone and sustain and a sweet break up until about halfway on the volume, then the break up becomes quite flubby and unusable(using a celestion vintage 30).... will the speaker line output transformers remedy this? do i connect the OT's to the speaker output directly, apparently the amps out is 8ohms and the new OT's are 4ohms, do i connect a pair in parallel?(i have 4 of them).anything more complex i'll take it to a local tech, i'm just hoping its a simple install. here's the OT's... http://cgi.ebay.com.au/ws/eBayISAPI....m=120396224663 .any help appreciated, thanks for looking!

[6267]

I think the 70v and 25v PA lines are like 100-200 ohms and 60 ohms or so, but I'm not sure. That would not be working right with an 8 or 16 ohm speaker attached. Instead of using Amp->OPT->Speaker Matching->Speaker setup, have you considered just using some different OPTs? It's generally not hard to swap opts...after you get the rivets out . I've never really used the 6gw8s, just the 6bm8s and they seemed to like a load between 7k and 10k ohms, a lot like a 6K6. Plenty of old radios used 6k6 or 6F6, so there are probably some nice vintage OPTs available. Of course the line matching transformers work, and they do give you the option of running speakers in every room .