Low wattage Plexi

[Littlewyan]

Has anyone here got any ideas for a low wattage plexi? I'd love a Marshall Plexi style amp for the bedroom but even two 6V6s running at 250V push out 10W and thats pretty loud. I know some guys at AX84 used the 6SN7GTB but its a valve thats no longer made so can be hard to find and needs a OT with a 22K Primary Z!

[pablogt]

The Heyboer HTS-9565 OT is THE OT for a 6SN7GTB plexi build. I had no problems sourcing it directly from Heyboer. There are plenty of 6SN7GTB around at reasonable prices

http://www.thetubestore.com/Tubes/6SN7-Tube-Types

[Littlewyan]

Ah yes but this is all in America, I live in England where in terms of OT and Valve availability outside of the norm there is sod all. You can get plenty of valves but only commonly used types.

[pablogt]

I live in Madrid.... You just have to pay VAT to the carrier when your OT arrives. You can get the tubes in Europe at http://www.banzaimusic.com/search.php?m ... rch&page=1 , http://www.uraltone.com/catalogsearch/result/?q=6SN7GTB , http://www.tubeampdoctor.com/catalog.ph ... anguage=en and many others, as well as ebay.

P.

[jazbo8]

Ah yes but this is all in America, I live in England where in terms of OT and Valve availability outside of the norm there is sod all. You can get plenty of valves but only commonly used types.

Mouser has the Hammond 125A which works for the 4-4-0 Studio. Here. If you have 16 Ohm speakers, some of the OPT found here can work as well. 6SN7 is a very common tube, you should have no problem getting it.

[d95err]

Even a 0.5W amp is way too loud for bedroom levels if you crank it (even with a small inefficient speaker). The only way to get the volume down is using some type of master volume, attenuator or power scaling.

[10thTx]

You could consider a version of the SoLow Watt amp using a VVR to dial it down to one watt:

http://ampgarage.com/forum/viewtopic.ph ... w+watt+amp

The ECL84 tubes are around 3-4 watts in a push/pull. So, that would be pretty easy to dial down to 1 watt or less with Dana Hall's VVR.

I don't know if the PPIMV is really needed with VVR also being used?
I'd probably remove it and use 220k resistors to ground if VVR is used.
OR ........ just VVR the ECL84 pentodes and use the PPIMV.

With respect, 10thtx

[10thTx]

Here are some chassis gut shots of another person who built this amp and
their review of the tone.

http://el34world.com/Forum/index.php?topic=13151.0

With respect, 10thtx

[Cantplay]

12ax7 into 6922 as power tube will get you close to 1/2W.

John

[Stevem]

I gotta add my 2 cents on this!
First off the Plexi cranked sound that we have all come to love be it out of a 50 or 100 watter has a large large part of its mojo derived from being blasted out of a 4-12" cabinet,
There is NO WAY to get that big part of the way a guitar reacts when standing in front of those speakers at bed room volumes!!
The best set up for home use that I have found is a amp of no more than 1 watt that has both power scaling and a attenuator,/ resistor pumped thru no more than a 8" driver in a ported cabinet.

[Littlewyan]

Thanks for the responses guys. That SoLow looks like a real winner. I'm a bit torn between an amp like that and the P1Ex from AX84. Mainly because if I built the P1 I could fit it into this chassis http://www.ampmaker.com/store/Punched-c ... d-1x9.html which would fit into this case http://www.ampmaker.com/infocentre/thread-32.html

Pretty neat don't you think? Could then just overdrive it with my SHO.

It wouldn't cost that much more to build a higher gain amp such as the SoLow but then the case would be so much bigger. I was thinking about using a ECL86 which I believe is a Triode/Pentode valve so I could add an extra gain stage to the P1, but I'm really not sure if having a gain stage and output stage in the same tube is a good idea. Worked for old record players but guitar amps? Not sure.....

Steven - I understand what you're saying, I wasn't going for an exact Plexi Tone, I just meant sort of ball park.

I should also have that I do have an attenuator but even on a 18Watt Amp it sucked a lot of life out of the Tone by the time I got down to bedroom level. With a 5 Watt Amp I wouldn't have to attenuate the signal as much.

[10thTx]

I'm really not sure if having a gain stage and output stage in the same tube is a good idea.

It works great! Check out Geezer's Little Wing 6BM8 build AmpGarage or the EL34 World. Fantastic amp using triode/pentode. I've built one.

I have zero agenda for you and certainly would want you to build whatever you think is a best fit for you. I just wanted to say that the triode/pentode for the LTPI and power tubes works just fine, IMO.

The SoLow Watt was just an idea that I was throwing into the mix to consider. You may or may not like the build?

With respect, 10thtx

[Littlewyan]

I like the look of the build very much. What I meant was if I used an ECL86 in that chassis I linked then I could build a P1 with an extra gain stage. So would still be single ended but will have a lot more gain! Would be like a HO or SEL from ax84 but without the Cathode Follower.

[johnnyreece]

Just to throw in my $.02, I've built a 6SN7 amp recently, and yes, it is still quite loud if you crank it. However, my power scaled Rocket, with all 4 EL84 cranking, I prefer that with VVR than trying to play my 6SN7 quieter. Count that as a vote for VVR.

[Littlewyan]

Or what about LED/Diode Clipping? That can sound alright if done correctly.