V1, V2, V3 in a Hot Rod Deville - what do these preamp tubes do?

[dirtdog]

OK, so a bunch of us have been trying or thinking of trying different preamp tubes in our Hot Rods. I'm thinking of doing the same. But before I go on this journey, I'd like to get a better handle on the nuances of the HR's preamp circuitry

My question is: "What do the V1, V2, V3 tubes in the preamp section of the Hot Rods do? "

If I've got Mesa 12AX7s in these three positions what would making a change from these to any of these others (such as 12au7, 12at7, 5751, 7025, ECC81/82/83/832) do for my tone?

DD

[rudutch]

if memory serves...

V1 - channel 1
V2 - channel 2
V3 - PI


http://www.fender.com/support/amp_sc..._Schematic.pdf

[dirtdog]

if memory serves...

V1 - channel 1
V2 - channel 2
V3 - PI


http://www.fender.com/support/amp_sc..._Schematic.pdf

thx rud....

I can see how the preamp tube in V2 could affect gain in channel 2, but, what does the preamp tube in V1 do for channel 1?

What does the tube in V3 do for the phase inverter?

What effects do these have on overall tone?

DD

[rudutch]

I had some success with using lower gain tubes in my HRDV
You can try some different tubes, they are reasonably cheap.
I am not a big fan of EH 12ax7's

Linky for gain listings
http://www.thetubestore.com/gainfactor.html

I have had good luck with Triode Electronics (Chicago) others here have also posted some good sources.

The search function is your friend :)

[telecustom]

I went with JAN Phillips 5751's in V1 and V2 and an Electroharmonix 12AT7 in V3 in my HRDx...and Svet power tubes. I liked the results.

[NTBluesGuitar]

I put NOS Sovtek 6N3Cs (6L6 equivalent) in the power section, an NOS GE 12AV7 in V3, an NOS RCA 12AZ7 in V2, and a 12AX7 in V1. It really calmed the amp down and warmed it up.

That was before it died and I gutted it.

[dirtdog]

I had some success with using lower gain tubes in my HRDV
You can try some different tubes, they are reasonably cheap.
I am not a big fan of EH 12ax7's

Linky for gain listings
http://www.thetubestore.com/gainfactor.html

Awesome link and very helpful.

The search function is your friend :)

...and my worst enemy - so many scattered posts somewhat related to this topic. Lots of descriptions on what people have tried in various preamp tubes/positions, but not a lot on what these preamp tubes actually do. Which is why I asked such a specific question in the first place.

For instance, do I want a tube that breaks up sooner on V1 if I want to keep things clean or would a tube like that do me better in V2 if I want a grindier tone on the dirty channel? Or is it the other way around? Or not anything like that at all? What happens if I don't put a balanced tube in V3?

That kinda thing.....

DD

[dirtdog]

Still making websearches and answering some of my own questions along the way....and found this:

http://kcanostubes.com/content/newsl...sp?ArticleID=5

Can this chart be reinterpreted for the Deville preamp tube layout or is there a similar type of thing somewhere for the Deville?

Like, if I look at the V1 position, I should keep the best quality 12AX7 in that slot to ensure maximum clean headroom (?), presumably. If I'm after more grit on my clean channel, I could go for a tube with a lower gain factor (i.e. 12AT7, 12AY7, ECC81/82)?

If I want to have a gritter drive channel (V2 for the Deville), I employ the same concept as in V1?

And I should put a high quality 12AX7/ECC83 in the V3/phase inverter position - for what reason?

DD - stupid about this stuff, but slowly getting smarter.....




DD

[rudutch]

Lets see if I can clarify. I will use my old HRDV as a reference.
Ch 1: if you ran it around 5 (?) if sounded great. Unfortunatly it would about peel paint at that level. I left this one a 12ax7
Ch 2 was not to my liking, I used a lower gain tube whick resulted in me being able to turn it up to 5 without the chainsaw grit / distortion

This improved the overall sound of the amp. I then put a lower gain in the phase inverter (which should not change things) but it allowered me to turn it up to 6 or 7 before the paint started peeling.

I also had a couple dozen preamp tubes of different gain factors to try. I did a lot of trial and error. It has been a few years but I think I went 100% ch1, 60% channel 2 and less than that for the phase inverter

I realise this is backward from what you want but for me it made the amp more useful. The breakup at higher levels was not a 'preamp distortion' but actully a bit of power amp tube breakup.

Also, if you don't have an isolation room, playing at that volume level does not always go over big with those you live with.

' I am not a big fan of pedals (stomp boxes) but I did find that they work well when you can't run the amp 'opened up' I tried several and the old "DOD 250" worked best for me.

anyway, lowering the gain in the preamp position will allow you to turn the volume knob up higher before you start to hear the grit starting.

hope that helps

[boobtube21]

Each preamp tube amplifies the signal a little bit. The power amp tubes amplify the signal, well, a lot.

If I'm not mistaken, I think (someone correct me if I'm wrong) V1 amplifies the signal for the clean channel, V2 amplifies the drive channel signal, and both halves of V2 amplify the 'more drive' channel. I think.

Or, V1 does clean and drive, V2 is added in for more drive. I knew at one time.

Is that what you were asking, or were you talking about the effects of what different tubes would do?

If you want to learn about tubes, there are a lot of great books out there. My favorite, which covers everything from tuning your guitar to playing it, to the guitar innovators of our time, to basics of amp/guitar circuitry is "The Guitar Handbook"

Check it out

[JAM]

V1A and V1B Drive and Clean
Tone stack between V1B and V2A
V2A Drive and Clean
V2B switched in for 'drive'

(Cathodes on V2A & V2B are bypassed on 'more drive')

V3 is PI

[boobtube21]

Ah, I see. Thank you JAM.

[dirtdog]

Is that what you were asking, or were you talking about the effects of what different tubes would do?

Well, I was asking both initially, but I'd like to know more primarily about the first question, how does the preamp section function in the Deville rather than what others are running in the preamp.

I know what kind of sound I'm getting right now and I know where I'd like to get it to but need a map to get "home", so to speak, rather than directions to someone else's house.

DD

[dirtdog]

Ah, I see. Thank you JAM.

Now I'M more confused....;-).

JAM - So putting a tube with a higher gain factor in V1 will affect both the clean and drive channels in some way? And putting a tube with a lower gain factor in V2 will do the same.

I'm gathering it's not a straightforward as some think it is - incl. my local music shop guys.

boobtube - thanks for the link to the book, I think I need to check that out.

DD

[ziess]

--

[JAM]

Now I'M more confused....;-).

JAM - So putting a tube with a higher gain factor in V1 will affect both the clean and drive channels in some way? And putting a tube with a lower gain factor in V2 will do the same.

DD

Yes, it will effect both channels. The HRDlx amps really should be considered 'Gain Switching' since a great deal of the circuitry (including the tone controls) are common to both clean and drive modes. I think experimenting with different tube types is the only way you're going to find what works well for the sound you're looking for. (Or search for threads for some recommendations.)

[NTBluesGuitar]

Or look back at posts #5 & 6 above...

[dirtdog]

Or look back at posts #5 & 6 above...

See what you're sayin' NT, but it still feels like directions to somebody else's house... I need the map...

Anways, thanks all for your input. The journey continues. I guess I'll have to get all experimental and ****....

DD

[boobtube21]

Dirtdog, there is no map. You have to get lost and find your way home.

[NTBluesGuitar]

Smart-alecky-ness aside, as I re-read this thread, I think I know what you're after.

Let me try to share my understanding of the subject (for what it's worth); I'm not sure about your level of knowledge of tubes, so please don't take anything that follows as my being patronizing.

The 12AXs are actually a dual triode tube; two triodes; wto sets of three (I know, there are 9 pins, but three are for the heaters which leaves 6). According to good ol' Wikipedia: "The 12AX7 is basically two 6AV6 triodes in one glass package. The 6AV6 was a repackaging of the triode from the octal 6SQ7, which was very similar to the older type 75 triode, which goes back to the mid 1930's."

My understanding is that the preamp tube has two halves that both independently do the same amplification jobs. I visualize it as the triode has an 'in', an 'out', and a 'ground'. I'm hoping that this is the 'map' part of what you're after.

V1, V2, V3, etc. stands for Valve One, Valve Two, and on, if I recall. Just a number or position.

Outside of that, amps do many many different things with the setups. The HRD is funky in that it uses different halves of the tubes for signal amplification, but shares one tone stack.

What I've done in efforts to learn this stuff is to start planning a construction of a classic circuit. Even if I'm just drawing out the circuit. This way, you can visualize what's going on in the amps without getting bogged down in the math.

Start with a Champ, then try the 5E3 Deluxe, and on. You'll start getting a good picture as to how everything relates to each other and then see how funky the HRD can be in comparison.

[dirtdog]

Dirtdog, there is no map. You have to get lost and find your way home.

There's some wisdom in that!

DD - map freak

[dirtdog]

Smart-alecky-ness aside, as I re-read this thread, I think I know what you're after.

Let me try to share my understanding of the subject (for what it's worth); I'm not sure about your level of knowledge of tubes, so please don't take anything that follows as my being patronizing.

Zero knowledge, so no risk of being patronizing....

Start with a Champ, then try the 5E3 Deluxe, and on. You'll start getting a good picture as to how everything relates to each other and then see how funky the HRD can be in comparison.

Thanks for the advice. That's going to be a chore for me. I the last time I ever looked a circuit or circuit diagram was Grade 9 when i took a basic electronics course and decided that it wasn't for me. However, your advice seems reasonable.....

I ended up digging a bit deeper on Justin Holton's site and found this HRD preamp analysis(which is also referenced in another TTF thread) which is basically what I'm looking for. Now I have enough of a map to keep me from getting too lost on my way home...

Next stop for me will be to try a pair of 12AT7s or ECC81s in V1 and V2 replacing the Mesa 12AX7s in there right now. I'll keep the Mesa 12AX7 in V3 for now and see how it sounds. That's in conjunction with the move from Mesa 6L6s to JJ 6V6s in the poweramp. I'll see how that sounds and report back with results.

Thanks boys.

DD

[dirtdog]

Update for ya'll.

Installed the JJ 6V6s in the power section and installed GT 12AT7s in V1 and V2. I left the stock Sovtek 12AX7 in V3. I biased the JJs at 42mV combined.

I'm liking what I'm hearing based on home playing and at band rehearsals. It feels like I'm using the amp to it's potential now. While a DRRI would be nice, unless I have reliability issues with the Deville, I'll stick with those two 12" speakers and this tube configuration.

Here's the breakdown:

Clean channel has some nice breakup at useable volumes at 4 on the Volume dial.

I hated the More Drive "channel" up to this point, but now I'm using it as such: Drive on 3, Master Volume on 5/6.

I also used the Drive channel wtih a bit of grit for dirty rythym playing and then boosting it with the more drive or my Sparkle Drive depending on the tune. I use my clean channel for more Robert Cray-like blues tunes in our repertoire and boost that with the SD for leads.

So far, so good. Very useable tone all around now. using lower gain tubes has made the Drive and More Drive much more useable now.

Now I just need to see how it all sounds on a gig.

DD

[trevorus]

I ended up with kind of an interesting mix of tubes in my experimentation. I used a Mesa 12ax7 in V1, a Chinese unlabeled 12ax7 in V2, and a GT Sovtek 12ax7 in V3. I have not had a change too turn it up too loud yet, but the drive channel is plenty aggressive, without the buzz saw effect. It sounds very natural. I will also say that I did some tone stack modifying (the mid control pot thing). It is a completely different amp from when I got it, and it sounds 1000x better than when I got it.

[dirtdog]

Cool, trev.

Reliability issues aside, I think these amps are pretty decent - a few slight modifications can make them very decent. As I mentioned earlier on, I dig the 212 configuration.

It'll take me a while to dial things in I'm sure, but at least I can dial them in. I was not able to do that with stock setup - just too damned loud and the drive/more drive just sucked.

Here's to keeping the HRDv torch burning! (for now) (until the next new shiny thing comes along).

DD