Groove Tubes 928-PR Substi-Tube?

Johnny Halo · March 29th, 2008, 06:41 PM

Any one try these out?

Especially in a PR?

Specifically PRII?

Thanks.

Tremo · March 30th, 2008, 12:45 AM

What is it?

Johnny Halo · March 30th, 2008, 01:02 AM

Whoops, sorry.

They are adapters, similar to THD yellow jackets, allowing you can run el-84's in place of your 6L6/6V6's.

I believe they turn your amp into Class A reduce and your output to drive the tubes into smooth tubey overdrive.

Tremo · March 30th, 2008, 03:17 AM

Class A? Please, not again.........

Why on earth would someone want to use those in a 6V6 amp anyway? Makes no sense at all.

Johnny Halo · March 31st, 2008, 12:01 AM

Something against Class A?

FWIW, I was looking into these due to reviews stating it gives a Vox-like sound to the amp.

Scott S · March 31st, 2008, 12:14 AM

The adaptors won't make your amp Class A, they just let you use different tubes.

Tremo · March 31st, 2008, 04:18 AM

Quote:

Originally Posted by Johnny Halo

Something against Class A?

FWIW, I was looking into these due to reviews stating it gives a Vox-like sound to the amp.

You gotta be kidding. Man I have some real estate on the moon you may like. Wake up my friend, don't fall for such BS idiotic hype advertising it is pure BS. Those damn things won't make your amp sound like a Vox. If you want Vox tone buy a Vox. There is a helluva lot more to Vox tone than just the damn EL84s.

And regarding the myth that is "class A", please do some reading on this board. Plenty of references as to how that is all just so much more BS. Do a search.

Johnny Halo · March 31st, 2008, 12:11 PM

Um....OK

Any thoughts as to they will cut the output allowing you to drive the amp more?

JDO · March 31st, 2008, 01:13 PM

ahhh, give the guy a break. he's got 8 posts. as we know, class a is widely misunderstood by people because of sales people spouting things to get top dollar.

just to help you out, changing tubes won't change the class of your amp. nor will changing the bias. cathode biased el84's are not class a. as tremo said, if you do a search on this you'll turn up a lot of information on this topic. and not just on this board :)

JDO · March 31st, 2008, 01:17 PM

Quote:

Originally Posted by Johnny Halo

Um....OK

Any thoughts as to they will cut the output allowing you to drive the amp more?

i can't comment on them since i've never used them. i'll say this... they will change the sound of your amp. you might like it, and you might not. and i would assume if you had an adaptor to use a set of el84's in a 6l6 amp it will put out less volume. again, it will also change the sound.

if you like the sound of the amp you have but want to get more tube breakup, i would suggest an attenuator. i have a weber mass and i'm quite happy with it.

hope that helps.

klasaine · March 31st, 2008, 01:43 PM

I've never used the GT version but I have used the THD 'yellow jackets' - 6L6 to EL-84.
As mentioned above they will of course not change the "operating class" of your amp but they will drop the output by as much as 1/2 and definitely change the feel and tone.
I was using them in a 2-12, 60 watt Fender HR DeVille. The amps tone was a little darker, distorted earlier and felt a little looser overall. At the time and for this particular gig, they were exactly what I needed. YMMV.

marshman · March 31st, 2008, 01:59 PM

And it seems to me that you'd probably not lose much in the power stakes by swapping 6V6s for EL84s...they tend to have roughly the same output in most situations. 5 or 6 watts each single ended, 15-22 per pair, push-pull, depending on OT.

They will sound a lot different, though. Most people feel that 6V6s emphasize the lower and low-mid frequencies while EL84s emphasize the upper mids. If you can get 'em cheap, or try 'em in YOUR amp, I'd say go for it--what've you got to lose?

hwestman · March 31st, 2008, 05:33 PM

Well almost...I have used ToneBones (which are pretty much the same as the substitubes) in my PR2. I liked it a lot!

Makes the tone a little softer in the high end and the overdrive slightly smoother and more gradual.

It also makes the amp sligthly quiter, but very subtly.

Now I am back to the 6V6:es but that was because I transferred the Tonebones to my Super Champ. They made a very positive contribution there as well.

Overall I think tube adapters are great fun. I also have the Tonebone Triode version which give a really loose feel and significantly lower headroom.

They´re also great for recording when you want a slightly different flavour.

Johnny Halo · April 1st, 2008, 03:55 AM

Thanks for the positive input, folks.

I have used, bought and sold enough amps to know that changing a tube or two is not gonna change the operation of an amp. As I stated, I was more interested in the tonal changes of switching. And, I also know that if you want steak, order steak - not fillet of steak-umms.

I found mention of the 928's and was curious - you guys have been a big help. Thanks again.

Comfortableman · April 2nd, 2008, 05:14 AM

I tried them in my -78 Twin Reverb. Replaced all four of the 6L6-tubes and got a nice sound. It didn´t turn the amp into a Vox though, but the sound got slightly "Voxier". Or more of that Laney AC-30, or Peavy Classic 50, sound. It definitely didn´t sound exactly like them, but it sure got close. It lost some of the bottom and the warmth of the Twin reverb, and got a nice bright sound. It sounded a bit compressed almost, and there was a change in volume also. The overall sound was at bit smoother and quieter. Still, I couldn´t get the amp to break up though. Well maybe it would sooner or later, but then again I´d rather not be in the same room as the amp with the volume above 5. I also tried the amp with two of the output tubes pulled, and with only one of the speakers connected. With that setup I got quite close to the sound of the Blues Jr Tweed I had next to my Twin. All in all I found that I missed the original sound of my Twin, which is the reason why I got it in the first place. I have to say that it was nice with the EL84 tubes for a change, but if you want the real deal I guess you´ll have to get a Vox or a Peavey or whatever. You could also use two of the EL84´s with two of the 6L6´s and get a nice combination. Still, I found that it wasn´t quite a Twin Reverb and not quite a Vox, or not quite anything at all really. Just a nice change. I bet they would be useful in a studio, though, as it´s fairly easy to get some different sounds out of one amp.

March 29th, 2008, 06:41 PM	#1 (permalink)
Johnny Halo TDPRI Member Join Date: Jul 2006 Location: USA Posts: 15	Groove Tubes 928-PR Substi-Tube? Any one try these out? Especially in a PR? Specifically PRII? Thanks.

March 31st, 2008, 01:13 PM	#9 (permalink)
JDO Tele-Holic Join Date: Mar 2003 Location: Pittsboro, NC Posts: 603	ahhh, give the guy a break. he's got 8 posts. as we know, class a is widely misunderstood by people because of sales people spouting things to get top dollar. just to help you out, changing tubes won't change the class of your amp. nor will changing the bias. cathode biased el84's are not class a. as tremo said, if you do a search on this you'll turn up a lot of information on this topic. and not just on this board :) __________________ clean as a whistle

March 30th, 2008, 12:45 AM	#2 (permalink)
Tremo Banned Friend of Leo's Join Date: Mar 2003 Location: Silicon Valley, CA, USA Posts: 3,803	What is it?

March 30th, 2008, 01:02 AM	#3 (permalink)
Johnny Halo TDPRI Member Join Date: Jul 2006 Location: USA Posts: 15	Whoops, sorry. They are adapters, similar to THD yellow jackets, allowing you can run el-84's in place of your 6L6/6V6's. I believe they turn your amp into Class A reduce and your output to drive the tubes into smooth tubey overdrive.

March 30th, 2008, 03:17 AM	#4 (permalink)
Tremo Banned Friend of Leo's Join Date: Mar 2003 Location: Silicon Valley, CA, USA Posts: 3,803	Class A? Please, not again......... Why on earth would someone want to use those in a 6V6 amp anyway? Makes no sense at all.

March 31st, 2008, 12:01 AM	#5 (permalink)
Johnny Halo TDPRI Member Join Date: Jul 2006 Location: USA Posts: 15	Something against Class A? FWIW, I was looking into these due to reviews stating it gives a Vox-like sound to the amp.

March 31st, 2008, 12:14 AM	#6 (permalink)
Scott S Tele-Afflicted Join Date: Dec 2005 Location: SW CR IA US NA PE Age: 28 Posts: 1,922	The adaptors won't make your amp Class A, they just let you use different tubes.

March 31st, 2008, 12:11 PM	#8 (permalink)
Johnny Halo TDPRI Member Join Date: Jul 2006 Location: USA Posts: 15	Um....OK Any thoughts as to they will cut the output allowing you to drive the amp more?

March 31st, 2008, 01:43 PM	#11 (permalink)
klasaine Tele-Afflicted Join Date: Nov 2006 Location: los angeles, ca Age: 46 Posts: 1,572 12 Photos	I've never used the GT version but I have used the THD 'yellow jackets' - 6L6 to EL-84. As mentioned above they will of course not change the "operating class" of your amp but they will drop the output by as much as 1/2 and definitely change the feel and tone. I was using them in a 2-12, 60 watt Fender HR DeVille. The amps tone was a little darker, distorted earlier and felt a little looser overall. At the time and for this particular gig, they were exactly what I needed. YMMV.

March 31st, 2008, 01:59 PM	#12 (permalink)
marshman Tele-Holic Join Date: Feb 2007 Location: SE PA Posts: 987	And it seems to me that you'd probably not lose much in the power stakes by swapping 6V6s for EL84s...they tend to have roughly the same output in most situations. 5 or 6 watts each single ended, 15-22 per pair, push-pull, depending on OT. They will sound a lot different, though. Most people feel that 6V6s emphasize the lower and low-mid frequencies while EL84s emphasize the upper mids. If you can get 'em cheap, or try 'em in YOUR amp, I'd say go for it--what've you got to lose?

March 31st, 2008, 05:33 PM	#13 (permalink)
hwestman Tele-Meister Join Date: Mar 2003 Location: Stockholm, Sweden Posts: 394	Well almost...I have used ToneBones (which are pretty much the same as the substitubes) in my PR2. I liked it a lot! Makes the tone a little softer in the high end and the overdrive slightly smoother and more gradual. It also makes the amp sligthly quiter, but very subtly. Now I am back to the 6V6:es but that was because I transferred the Tonebones to my Super Champ. They made a very positive contribution there as well. Overall I think tube adapters are great fun. I also have the Tonebone Triode version which give a really loose feel and significantly lower headroom. They´re also great for recording when you want a slightly different flavour.

April 1st, 2008, 03:55 AM	#14 (permalink)
Johnny Halo TDPRI Member Join Date: Jul 2006 Location: USA Posts: 15	Thanks for the positive input, folks. I have used, bought and sold enough amps to know that changing a tube or two is not gonna change the operation of an amp. As I stated, I was more interested in the tonal changes of switching. And, I also know that if you want steak, order steak - not fillet of steak-umms. I found mention of the 928's and was curious - you guys have been a big help. Thanks again.

April 2nd, 2008, 05:14 AM	#15 (permalink)
Comfortableman TDPRI Member Join Date: Jan 2008 Location: Sweden Posts: 13	I tried them in my -78 Twin Reverb. Replaced all four of the 6L6-tubes and got a nice sound. It didn´t turn the amp into a Vox though, but the sound got slightly "Voxier". Or more of that Laney AC-30, or Peavy Classic 50, sound. It definitely didn´t sound exactly like them, but it sure got close. It lost some of the bottom and the warmth of the Twin reverb, and got a nice bright sound. It sounded a bit compressed almost, and there was a change in volume also. The overall sound was at bit smoother and quieter. Still, I couldn´t get the amp to break up though. Well maybe it would sooner or later, but then again I´d rather not be in the same room as the amp with the volume above 5. I also tried the amp with two of the output tubes pulled, and with only one of the speakers connected. With that setup I got quite close to the sound of the Blues Jr Tweed I had next to my Twin. All in all I found that I missed the original sound of my Twin, which is the reason why I got it in the first place. I have to say that it was nice with the EL84 tubes for a change, but if you want the real deal I guess you´ll have to get a Vox or a Peavey or whatever. You could also use two of the EL84´s with two of the 6L6´s and get a nice combination. Still, I found that it wasn´t quite a Twin Reverb and not quite a Vox, or not quite anything at all really. Just a nice change. I bet they would be useful in a studio, though, as it´s fairly easy to get some different sounds out of one amp.