dcribbs1412 wrote:Congrats Doveman
Looks great...that was quick
I'm guessing your looking at the vibrato hole for a possible place for a imp switch. How are your voltages looking?
Darin
Thanks. Pretty easy build compared to the Brown Note ... Only a couple of small issues.
Yes, I have a impedance switch on the way that fits a 3/8" hole and may fit under the top of the amp. If not there, I'll put a plug in it.
There are no target voltages on the schematic. However, I followed the checklist and double checked everything. It's dead quiet and sounds great. I want to some 6L6s in it, rebias and see how that sounds too.
As far as voltages go maybe a looking at a DR schem can give a general
idea of voltages
Not sure if the voltages will stay the same with the reverb tank in place.
But like you say It's dead quiet and sounds great...run with it.
6l6's should make a difference in the clean headroom.
I think the PT will even run EL34's if the sockets were wired for such.
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Well a good build I think. I did find one error yesterday. There are two star grounds - one for preamp - one for power amp. I had placed one of the power amp grounds in the preamp. I sampled some of the voltages and sent them to David - it appears to be built correctly. David says with 6L6s it is really close to the voltages on a Vibrolux Reverb and it is pretty close to the SF schematic voltages. Cabinet, reverb tank and speaker will be here in a few weeks.
Thoughts:
* It sounded pretty good at low volumes but I thought it was a bit cold/ harsh - like it was biased cold. I spent a good part of the weekend playing with it and I'm starting to feel comfortable. It appears that it is safe to bias a bit higher with 6L6s than the recommendation. Playing with the controls I found a lot of interaction - the sounds are in there.
* I tried some Tung-sol 5881s and really like the looser feel. I think these really match the amp well and can easily handle the 420v. I will play with these for a while.
* For me the 6L6s were much better at slightly higher bias. After playing with the controls, a much improved sound - very blackface. I may end up there in the end. Sort of a Vibrolux in a light 1x12 grab and go.
* I think either 5581 or 6L6GC fits me better than the 6V6.
* A 12AT7 in PT slot sounds better to me. I may put one in reverb slot once the cab arrives.
* The raw control is not something I think I will use or maybe it takes a while to figure out. If used, I wouldn't think you could go over 2 or 3.
* the master volume is very nice. Really done well and effective.
A few things I still want to try:
* ordered some 2a rectifiers - 5V4 and 5R4 as options to the 5Ar4/GZ34 - for a bit more sag.
* Switching OT impedance - while I wired this up a bit cleaner with the 8 ohm tap, I still left myself some OT lead for possible future switching between 4 & 8 ohm taps.
* Looking forward to the Eminence RWB that comes with the cab - different flavor.
* There are a few mods recommended to take it more toward Fender specs but I will play it a while in it's final form before trying them.
I'll post some clips after I spend some more time with the amp as I don't think I've figured it out yet.
Running iOS7 on my phone has definitely made typing on the touch keyboard more difficult.
Substituting a 12AT7 in the PI reduces the drive into the power stage, which is in some ways similar to increasing the power tube idle current. I would experiment with hotter bias if it sounds better, up to say 75% based on cathode current.
Ordered a set of Winged -C- 6L6s and that helped a lot. I have also been playing with the amp for a week. The treble and middle settings need to be run a little lower than I am used to. It makes the harshness go away. I was able to put the 12ax7 back in the PI slot and it sounded good too. I ordered another JJ 5751 and I'm trying it in the PI, as well. It may be better than the others. I'm not even going to try the 5R4 and 5V4 rectifiers that I ordered. The Winged C adjustment and getting a feel for the tone controls made a big difference.
Also, I was able to install the OT impedance tap switch after all.
So, pretty happy in the end. I'll keep playing it until the cab shows up. Maybe make some YouTube clips a bit later.
Last edited by doveman on Sat Oct 19, 2013 2:27 am, edited 1 time in total.
If output tubes make that much difference, the amp is in good shape! I love those Winged Cs; glad to hear you could get them. Blackface Tonestack takes some getting used to: too bright, too dark, mid seems to do nothing. Play with treble up everything else down; then bass up everything down. Somewhere, you'll find a sound, but it's a pretty narrow range. The mid control is almost cosmetic.
Combo cab is shipping today! Should be here Tuesday.
It's coming with a WGS G12C ceramic and I recently acquired a G12A alnico that I have mounted in a tweed 1X12 extension cab. One of these will end up with this combo - one will end up with the tweed.
Excited to put the chassis in a proper cabinet - hard to read upside down.
dcribbs1412 wrote:Congrats doveman
great looking build.
Which speaker did you go with?
Darin
Thanks!
I'm going to leave the WGS G12C in it until it breaks in a little. I've already been swapping the output to the tweed 1x12 with the G12A in it. They both sound pretty good but the alnico is a bit more broken in. There's no rush - one will end up with the tweed, the other in the combo. They sound good paired as a 2x12 too. But that flavor WGS American speaker is a good choice either way.
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