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This has all given me a little bit to think about...

I understand the difference between line and instrument level, although i was under the impression that I could add a simple booster circuit at the output of the "preamps" to bring them closer to line level.  Also, I've been told that inserting a buffer circuit between the Treble and Volume pots on the Sunn circuit greatly improves tone and volume due to loss from the tonestack. 

The input sensitivity on my poweramp is just above 1v, and the input impedances are 10K ohms unbalanced and 20K ohms balanced.  I should be able to get close to that with a booster circuit like an LPB after each preamp to boost the level up and bring the impedance to 10k... right?

I found a cool looking JCM800 emulation which looks quite nice (http://uk-electronic.de/onlineshop/product_info.php?cPath=105_248&products_id=941&osCsid=7676696ac9f3fed0bf317787b4be071f)

You may find that in order to get the grunt of a T (or the Fender for that matter) you may have to route them thru a cabinet simulator.  Sort of the same idea as using a Line6 POD with the "Air" setting on and choosing a speaker configuration.

Oh really?  The poweramp will be running through some cabs, so won't this sound a bit weird/blanketed?  A speaker sim going into a speaker?

my problem with this post is wrapped around terminology. words are important and it is important to make a distinction between a preamp and an effects pedal because they are not the same thing. so when you tell me you have a sunn model t preamp or a fender style preamp, those are both tube preamps. keeping them solid state doesn't mean you go out and get a wampler black 65 and an earthquaker acapulco gold pedal and feed those into the power amp like that is the same thing.

I'm a bit confused by what you mean. I suppose it's a bit of lax terminology, but what i was looking for was something like a FET emulation of the preamp section of an amplifier.  That's what the Model T preamp I mentioned is.  I wasn't suggesting that I plug an acapulco gold straight in as that's a fuzz pedal rather than a tone-shaper.

I was looking for a pseudo-preamp in a pedal kind of thing?  Or does that confuse things more?...
I thought it would be understood what I was looking for - effectively a circuit to colour and add harmonics to the front end of a clean power amp so that it becomes useable as a primary amplifier.

Hope i've clarified things, although i might have just confused things more...  I'm not very good at explaining this type of thing lol.  I know what *I* want, but others may not get that.

Hmmm how about the Azabache?

http://diy.thcustom.com/shop/rog-azabache-pcb/

Yes, I've considered that.  It looks like a cool option but I'm not sure if it would have the headroom to drive a power amp.  Although maybe i could chain it with an LPB to bring up the volume going into the power amp?  Hmm...

I'm in the process of building a bit of a modular amp design-type-thing. I have a stereo QSC poweramp; and in the 1U space above it in the rack case, I'm going to have 2 preamps in half rack enclosures that I plan to chop and change depending on what sound I'm going for. My initial design is one side being a Sunn Model T preamp, and the other side being a Fender style preamp. I'm keeping it all solid state.

I have all the stuff to build the Model T preamp ready, and I have someone more skilled than me working on a schem/pcb for a Fender preamp. However, the latter isn't going to be ready very soon, and I'm recording in early April. I need to get one other preamp finished ASAP, and I'm drawing a blank on what to build. I'm looking for a PCB that's readily available. I've tried many a tagboard build, but I'd rather not use one (mainly as I can rarely get them to work). I don't have time either to design and prototype a PCB design, although feel free to suggest ones for future builds.

I was considering one of the amp emulations from ROG, but couldn't find any information about how they would behave going into a poweramp. Another one I was looking at was the OLC Orange Peel but, again, not much information on how it works straight into power amps. Has anyone built a preamp/amp emu/amp-in-a-box that they've used going either into an effects loop or power amp which they can recommend building? I just want something clean/crunchy which I'll drive with fuzz pedals.

Yo!

Built this up pretty quickly as I only had a short amount of time after work to make sure it was ready for a gig tomorrow, but I'm pretty happy with how it's turned out.  This is a Bubble Font spec Green Russian Muff built on a Mudbunny board.  WIMA/NOS caps, carbon comp resistors (mostly), original KD3102 transistors, and KD522b diodes.  Lettering is Stazeon ink stamps.





Made a couple of little boo-boos in the offboard wiring (e.g. burnt a cap and wired the tone knob backwards) and it's not completely clean, but looks fine.  I know it works, but I don't have any amps in my house as I'm midway through moving.  I'll use it at my gig tomorrow full through my full rig and let you all know how it sounds. 

Time will tell whether using all these expensive and old components will actually enhance anything or just add noise, but we'll see.  Could be the best Muff ever!

Yep, I have the diodes that the layout uses.  I heard good things about LEDs through research on 250 clones people have made so I thought I'd try them.  That's why I socketed them, so I could switch them and see which one I liked more.

Ha!  I thought that my soldering may be the reason.  I think you can tell i'm a beginner
I'll re flow the joints and make sure there are no bridges and get back to you guys later.  Thanks for the help!

And yes, those LEDs are in place of 1N4148s.  I tried them and there was no difference so I just kept the LEDs in instead.  Is that alright using these 3mm LEDs?

I don't know what was going on with the pictures.  Something to do with the cloud service I'm using.  I've edited the original post. 

Thanks for the suggestions so far!  I'll keep looking.

Hey all,

Sorry if this turns out to be something incredibly obvious, but I'm still really new to this.
I'm building a DOD 250 from this layout http://tagboardeffects.blogspot.co.uk/2010/07/dod-250.html and I just finished it.  However, all I get is clean signal passing through.  The volume pot works exactly as it should, but turning the drive does absolutely nothing.  I've checked everything and it all seems fine.  All the polarities look ok (unless I misunderstood the diagram and got something the wrong way round).

Here are some pics (WARNING: SOLDER GORE!  ) sorry for the blurriness

EDIT: The pictures were acting strangely, so here's just a direct link to them.  These should work.

https://app.box.com/s/xamsvx77pqaz9rc4qnlc

https://app.box.com/s/w3tzcyooxfgh9yevqe53

Thanks!  Let me know if there's any more info you need.