Critics Wanted!

[ajeffcote]

I'm about to tear up my Deluxe Reverb-ish build and start again.  The sockets have been soldered and unsoldered so many times the pins are all loose and at the breaking point. I may even put in a new board and turrets, and a multi-tap OT. What I'm asking is for some of your experienced opinions on and advice about the wiring, lead dress, anything at all. If you see something I should have, could have done to make it better, something you would have changed,  any thing at all, I would really appreciate your advice. I have a lot of pics, I tried to get some good ones, but still there is a lot of wire in there so some things are a little hard to see. As I remove wiring and/or components I will shoot some more if I have more questions.
I think I did a fair job on it, but it's not as quiet as it could be, and it never has quite lived up to my expectations about the way it should sound. I'll probably build a new cabinet for it, maybe a head cab for the chassis and a separate speaker cab, to extend the life expectancy of my back a few more years.

[ajeffcote]

The normal channel was modded for a little more gain, as outlined in one of Gerald Weber's books. The weird tone stack mod is also per G. Weber, as a way to shorten grid wires.
The input grid stoppers for V1 and V2 are at the tube and covered in shrink wrap, and 2 conductor shielded cable was used there also. When I put it back together I'll use 1 input per channel only. The main filter is 1 40uf instead of paralleled 16uf caps, I think that works allright. The PI cap is a 40uf, and I think maybe that's making the amp too stiff, so I'll go with 16uf like Fender did. I plan to use a ground buss again, but this time it will be isolated from the pot backs, or maybe I'll leave it on the pots but isolate the pots from the chassis, to get all the pre-amp grounds in one spot like a star ground, but without all the separate ground wires.
 

[Slimtim]

looks like a nice build sorry it didn't turn out the way you hoped.maybe more thoughts on what you want out of it sound wise will give folks a better idea of changes you need to make.

[ajeffcote]

looks like a nice build sorry it didn't turn out the way you hoped.maybe more thoughts on what you want out of it sound wise will give folks a better idea of changes you need to make.

Yes, I know I'm vague on what I want it to be, I am not good at describing sound at all. I thought it sounded allright for the most part until I got to play an excellent blackface Vibrolux Reverb. I want to make mine a 6V6 version of that amp, so I'm sure of using 10" speakers, and I think a different OT will help.

[sluckey]

I would prune that tree limb full of caps and resistors stretched between the board and pots. Put the components on the board.

Put the dog house on that cap board so you don't get a surprise down the road when you reach up under the chassis to pull a tube or catch a gecko.

[ajeffcote]

I would prune that tree limb full of caps and resistors stretched between the board and pots. Put the components on the board.

Put the dog house on that cap board so you don't get a surprise down the road when you reach up under the chassis to pull a tube or catch a gecko.

I just took the cap off to expose the innards for inspection. Tree limb, duly noted.

[eleventeen]

Yours looks very well executed, to me...I assume you've made the mental comparison between this amp and the Vibrolux you played and made the appropriate "discounts"...by that I mean....

Most of us would be pretty happy to own & play through a BF Vibrolux so some part of what you hearing is hearing the nameplate....true?

To me, and I consider myself incredibly INsensitive to tone, 6V6's have a completely different type of sound than 6L6's.

I agree with you that the OT might make a lot of difference; if you have your (current) 6V6 amp with a high-quality MM output transformer, while comparing the sound to a Vibrolux that (I think) most would say has a somewhat undersized output transformer...plus you (presumably) are running a 12" speaker vs the 10" ones in a Vibrolux...

These are big, cornerstone differences

I think part of what I am getting at is that I would swap a smaller OT into the existing amp, just as it is, before tearing it apart. I know this may sound funny, but since we're just throwing out ideas and you asked...maybe you should buy & throw in a cruddy output transformer and see if you like how that sounds. I don't really see a lot to be gained by tearing apart what you already have. Personally, I *like* oversized output trannies because I am after more of a high-fidelity full range sound. But not everyone wants that.

[Slimtim]

another thought,if you like the 10" sound over 12" go ahead and switch that before tearing into the amp.that might make most the diff. between the 2 amps.

[embotone]

If I were to build that over, I would ditch the cloth covered wire and use some good pvc or teflon convered solid core wire. Just my personal preference. I find it much easier to work with and stays where I put it better.  I like to use wire strippers like this:  http://www.amazon.com/Irwin-Industrial-Tools-2078300-Self-Adjusting/dp/B000OQ21CA/ref=sr_1_1?ie=UTF8&qid=1379457350&sr=8-1&keywords=wire+stripping+tool.  It makes it easy to solder one end, route the wire and cut to length, and then strip the other end without pulling my nice wiring job out of shape.  Teflon wire can be more difficult to strip compared to pvc. I also would not bundle other wires together with the heater wires.

[HotBluePlates]

... you (presumably) are running a 12" speaker vs the 10" ones in a Vibrolux...

And that 12" is new vs. the ~45 year old speakers in the Vibrolux...

[ajeffcote]

This all makes sense, especially the OT and the speakers. The wires bundled? No signal wires, only A/C and the DC after the first cap. I guess that could cause a little interference. Duly noted. I like to play clean mostly, with occasional overdrive or "on the edge" hair. That VR has the most beautiful, full clean tone I have ever heard coming straight from an amp. So I'm looking for some well broken in 10s. May just get some new Weber alnico 10s and do the break-in treatment on them. The problem I have with buying old used speakers is kind of the same that I have buying old tubes. People don't generally want to sell the good ones.
After thinking it over some more, I probably won't bundle the DC wiring with the A/C again. At the point where I did it, it may or may not be a problem. But it's not a good idea. I'm getting some good out of this thread!

[eleventeen]

I looked at your heater wire bundling and I only saw AC line wires tied to your heaters, which is OK. Ordinarily I would have objected.

My guitar hero and pal Scott Henderson breaks in new speakers he buys by running a very low frequency (8-15 Hz) powered (of course) sine wave through them for half a day. If you don't have a function generator, you can get one online....and take the audio out of your computer, jam it into the input of an amp, and exercise your speaker!

[tubeswell]

Yep what the others have said about trying different OT and speaker combinations can yield widely varying (including great) results from different amp circuits. Your existing circuit might improve (to your ears) even more if you just hit upon the 'right' combo.

IMHO 6V6 amps sound better either in simple bluesy/tweedy amp circuits (with a limited number of gain stages) or with the PR or DR circuits. Even a 6G3 circuit is starting to get rockier. Remember that 6V6s don't have as-big-a-bias-voltage as 6L6s, so you don't need a lot of pre-amp stages to make them clip. 2 gain stages (or at the most 3 gain stages, with a bit of inter-stage attenuation - like the PR or DR) is more than enough. Having said that, in most amps, you won't be able to keep them clean when dimed.

[ajeffcote]

When I talk about playing clean, I mean clean and miked. I don't need a lot of headroom, so 6V6s are fine for that. And the Deluxe Reverb circuit is fine with me too. But my particular amp is lacking, and I think, like you all have pointed out, that the right OT and speakers will help. I'm still going to remove the circuit board and replace the tube sockets, change up he filtering a bit and there are a couple other things I want to try. I'll do another circuit board, with some different caps and metal film resistors but I'll be keeping the board I have now for another project, maybe a Twin Reverb.
Now that I have all these pics up, I will ask for a little more help. The noisiest part of the amp is the reverb, and when I turn that up the hum really becomes a problem. I'm guessing that's because of the proximity of the verb transformer and jack wiring to the heater wires. What do you think?

[eleventeen]

Re: reverb noise. There are several aspects (that can contribute) to this, but I would suspect transformer lead dress/placement, while *possible* is a bit less likely than some other aspects.

Things to try or think about:

First off, I would swap & test 12AT7 drivers; then I would throw a 12AU7 (much lower gain than 12AT7) in driver position; this will give you at least a partial sense of whether the noise is on the driver or the recovery side. The 12AU7 might be preferable to you anyway, as it is. You'll have to twist the "reverb" knob higher than 3-4 (the max I can use before excess surf sets in) to get the amount of verb you're probably used to.

Make sure your reverb can is properly grounded and that the wires inside the can are sound. If it's an older can, these can get to the point where there is only one teeny wire making the connection and that can mess with things. (Be gentle!)

Offhand, I'd think that noise is more likely to enter things on the recovery side because it's more of a high-impedance zone than the driver side. That's where you might wish to play with lead dress. Or place a B+ cap right near the recovery tube.

[ajeffcote]

A 12AU7 might be nice for a driver. I've got a nice Mullard 12AT7 in it now. I will give it a try.
The reverb, like I said, is the noisiest part  of the amp. But I normally play with just a touch of verb, maybe 2.5 on the knob. At that low of a setting the noise is not a problem. The amp is pretty quiet then. It's when I turn up the reverb and I have the volume up that it becomes a problem. For instance, with the volume on 7 I start turning up the reverb, at maybe 6 the amp is about to feedback without a signal. I just want to get the amp as quiet as possible.
With the feedback I have received from you all, I have decided to fix the issues and tweak some more before I do anything drastic. The speaker will get swapped for !0 inchers sometime soon, but for now I know I will learn more from tweaking here and there than I will from just starting over, which could leave me in the spot I'm in now.
Today I re-wired the inputs, shielded grid wires, cleaned up the ground buss wiring, reduced the PI supply cap from 40uf to 20uf. I used 33K for the input grid stoppers. No more hi/lo jacks, just one per channel.
I've got some different coupling caps I want to try and I should have it running again tomorrow. I'm leaving the "tree limb" tone stack for now. I've got some tests planned and I want to see if there is any difference in the noise floor between that and the board mounted tone stack.

[LHPcope]

I guess I am agreeing with what's been said before.  You are currently running 6V6s so stay with the MM OT for the time being and make the change in speakers.  Play the amp for a while and see where you are before further surgery. 

[eleventeen]

"but for now I know I will learn more from tweaking here and there than I will from just starting over..."

You're wise to see this, IMO. You're proposing to make a number of pretty dramatic changes, and IMO unless you do them one at a time, you're likely to confuse the issue of what made it or will make it more/less the way you like. The "rip it all out & start over" option *never* goes away.

[sluckey]

This is not really a critique, just a personal preference. I like to run the board interconnecting wires under the board. Each wire is routed under the board then up through a hole that's adjacent to the turret, And finally wrap the wire around the turret. I think this method looks cleaner and makes probe access easier. Take a look at my last two boards. May give you some ideas in case you decide to start over.

     http://home.comcast.net/~seluckey/amps/warbler/w_06.jpg

     http://home.comcast.net/~seluckey/amps/revibe/revibe_03.jpg

[ajeffcote]

Very clean, Sluckey! Nice work! You give me goals to aim for.

[ajeffcote]

Well, I have my DR up and running. I'm not sure what the problem was because I didn't trace a signal through the amp, but it is now sounding much closer to what I want to hear. I think I'll be there when I get the 2-10s installed (I don't even have them yet).
What I did was basically clean-up. The DC carrier from the rectifier to the standby switch, and back a bit was bundled with the heater and A/C supply. Changed that. Took the buss wire from the backs of the pots originally to replace it with sort of a buss/star combination, but I went back with the Marshall style buss, but this time I terminated at a bolt in the chassis by the normal side input jack, right at the corner of the board. Went with 1 input per channel with a 33K grid stopper mounted on the socket pin. I also did a neater job of wiring with the shielded cable than the first time around. I put the normal channel caps back on the board, using PS series OD caps, A .1 and a .022, and a Silver Mica 680pf for the treble. Changed the treble cap on the vibrato side to a 250pf poly-styrene. Changed the .1 in the PI from a 630V Mallory to a .1 400V, just for aesthetics. And the PI supply cap from 40uf to 20uf.
When I fired it up I was expecting a lot of noise, was ready to start moving wires around, but the amp is very quiet now. I can dime the volume, both tones and the reverb with a Strat plugged in (with said Strat turned the right direction) and while it is not silent, it ain't that far from it. And the chassis was directly under a 4 bulb fluorescent light fixture, 30" above it.
I lined the top of the cabinet with aluminum foil before I buttoned it up again. Now I think it's even quieter!
I'm shocked that it sounds as good as it does. I know I prefer the poly-styrene to the SM I had in the vibrato side to begin with, and I prefer the way the normal channel is now, although I do not know how much of that can be attributed to the cap change versus the tone stack's position. All the notes I play now sound much clearer and the amp is just more musical now. Maybe the 40uf was too much for the PI, but it "feels" better now too. I'm perfectly happy with the OT as is.
New amp honeymoon? Maybe. All I know is that I had previously made some small mistakes that made a potentially great amp sound mediocre. Because it sounds great now. 
Thank you for your help.