PPIMV & 1/2 Power Mod

[My Guitar Weeps]

I'm about to purchase a Ceriatone Plexi50 1987Lead from Nik. I'd like to play it at gigs as well as home. He's got a 1/2 power mod that he can do to it. I asked him if he could explain it to me, if it was a toggle switch that he added to the back of the amp and here's the answer I got:

It's a 50/25 speaker. It doesnt scale. It's a pentode/triode mode

I'm no amp tech, so I was wondering if someone would be kind enough to explain how this works?

Also I'm opting for the PPIMV. Is it preferred on the front or the back for most people? Anyone have any experience with this option on Nik's amplifiers?

I can't afford to make a high dollar mistake so I want to make sure I get the right options. I've been listening to sound clips and researching built kits and makers for the last two weeks. I really like the 1987lead tones. It sounds like just what I'm looking for. It seems that through Nik I'm also able to get the options that I want. I haven't heard anything real good about the reissues, not to mention that they're much more expensive and aren't handwired.

I want to be able to build my own so bad I can't stand it, but I have no understanding of electronics. I'm just not there yet. I'd really like to get a hold of some books that teach electronics and explain how tube amplifiers work inn laymans terms. If anyone has any recomendations in that department as well, I'd love to hear about them.

Robert

[phsyconoodler]

The pentode/triode mod reduces power by essentially turning your power tubes from pentodes into triodes.It does not give you half power,more like 2/3 power,and it alters the tone significantly.Some guys like it,some don't.
Waste of skin if you ask me.
The PPIMV is far better and it will get you what you need.Grind at low volumes.

[Blue Strat]

Pentode/Triode is a different wiring scheme for the power tubes. Probably worth having since it shouldn't cost much, but half power doesn't reduce volume much at all.

MV on the front is always nice so you don't have to "reach around"

[mark norwine]

Originally Posted by phsyconoodler

Waste of skin if you ask me.

I agree.

Just wondering.......

Why don't we call it "Pentode / Tetrode"? I mean....really: Tying G2 to the plates leaves 4 active components, not 3. So why do we call it "Triode"?

[VikingAmps]

That's a good question. And why do we call the beam Tetrodes in most of the amps we put them in Pentodes?

[topbrent]

I would have Nik do the LarMar master volume with the 2x250k pots on the front panel. If you dare to read it all, there is a 50page thread on it over at metroamps. It is the most convincing MV I have used.

Nik has a version of it using 2x500k pots, but the sweep is more friendly using the 250k pots.

PM jzucker, he has the LarMar MV it on his ceriatone plexi.

[JJman]

I had a pentode/triode switch on an amp and it was useless. It reduced the bass a little. I have a PPIMV on an amp now and it's very useful since the PI clips, and high volume hurts sometimes.

[My Guitar Weeps]

First off, thank all of you for your replies I really appreciate it.

And if any of you have any recommended reads that I should look into so I can get started down the road of "learning electronics & DIY amp building", I'm all ears! Anything that might of helped you guys along the way back in the day???

Lord Valve sent me the Navy's electronic course on CD with one of my purchases but it's like 5,000 pages long and covers all kinds of things.....

topbrent, it's funny you mention Jack because I've sent him some pm's about his amp. I actually tried to sign up on the Metro forums yesterday but it said that it was not open for new member registration??? Could you possibly email or pm me the link to hat thread about the LarMar?

From what a few of you have said, the 1/2 power switch is not as beneficial as the PPIMV. I was considering both mods.

I think Nik's opinion on the 1/2 power was that it's a $20 mod. If I don't like it, then keep it in the pentode mode. It would probably cost $50 or so to have it done in the states if I didn't get it and decided that I wanted it after I got the amp. Not a bad philosophy really. But if the general consensus amongst you veterans is that it's not a real good idea, then that's $20 to go towards something else.

The whole pentode/triode just brings up an additional situation.....knowing your tubes and how they function. Again, something else that I'd realy like to educate myself on. I can do the whole "google" thing, but I'd bet there are some people around here with far better resources than I'd come up with and that would help me become at the very least a little more self sufficient.

Thanks again for expressing your views and replying to my thread. I'm depending on them to make the right decision.

Mike K. I appreciate you chiming in too. You'll be hearing from me pretty soon about some tube recommendations for an amp or two

Robert

[phsyconoodler]

The 'internet version' of how to become a tube expert is not available in all areas.
Seriously,the only way to learn is to read everything you can get your hands on and work on tube amps.Build a few and learn for yourself.
Everyone today wants stuff instantly.The old school way of 'hands on' is one of the best ways to learn.

[hamfist]

With my Ceriatone 1987, I found that the PPIMV on it's own was not enough to get me the tone I wanted, at living room volumes. The PPIMV plus a Hotplate sounded great at pretty much any volume though.
I'm not saying that the PPIMV on it's own sounded horrible at living room volumes, but certainly did not sound as good as the PPIMV plus attenuator.
For gigging, I found the PPIMV provided ample volume reduction.
This was with the standard "old version" Ceriatone PPIMV though. Nik has updated since then. Definately sounds worthwhile seeing if he can install the Lar-Mar PPIMV.

[topbrent]

Could you possibly email or pm me the link to that thread about the LarMar Master Volume?

Here ya go. Hope you have a spare hour or so...

Starting on page 4....of 53 pages....
http://forum.metroamp.com/viewtopic....r=asc&start=45


It is a good read, and there are some great sound clips to prove the merit of this design.
It is a Ken Fisher (Trainwreck) design. Wonderfully simple, and with solid theory behind it.

Low parts count, too. 1 dual 250k audio pot, 2- 2.2M resistors to replace the 2- 220k resistors leading to the bias on the board.

As I understand it, you really are just "turning down" the power section. Not coloring it with added caps or unnecessary circuitry.

I think it's one of the better designs to come along in a while.

YMMV.

[My Guitar Weeps]

Originally Posted by phsyconoodler

The 'internet version' of how to become a tube expert is not available in all areas.
Seriously,the only way to learn is to read everything you can get your hands on and work on tube amps.Build a few and learn for yourself.
Everyone today wants stuff instantly.The old school way of 'hands on' is one of the best ways to learn.

Don't get me wrong, I'm not looking for a quick fix. I wouldn't think one even exists. I want to pay my dues. I'm just looking for a little guidence on where to get started :AOK. Trial and error like you stated is a big part of the fun, or at least I'd assume so.

hamfist, tha's great info!

Thanks for the link topbrent. I'll make the time!

Robert

[phsyconoodler]

Go to www.hoffmanamps.com and look in his parts list.He has a few books and DVD's of the instructional nature.Gerald Weber has a few books and DVD's out that are very informative.
There is a free online book by Jack Darr that explains some basics.
Many of the parts suppliers have books of all descriptions.
?Try 'London Power' for the Canadian slant on things,eh!

[My Guitar Weeps]

Thanks phsyconoodler!!!!!

I'll definitley look into your suggestions.

[My Guitar Weeps]

Well looks like I'll be getting first hand experience with the LarMar......

I just bought jzucker's Ceriatone Plexi. Should have it in a few days!

Thanks to all who posted