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Well there are a couple of bugs I need to find/fix, mainly a mountain stream sort of hissing sound thats always there. The amp was dead quiet before, now its gotta little hiss......... That being said, this amp sounds flat out amazing !! It is much louder than it was, with a lot more headroom as well. Sounds very full, robust. I used a mod Zaphod talks about and put a 2200uf bypass cap on the cathode resistor of the 6v6's, will put one on the EL84's as soon as another arrives. Very tight bottom end on the amp, shimmering highs. All this with an open back cabinet it hated a couple of days ago. I can't wait to hear it when my closed back 2x12 arrives. I havent really even started tuning the overdrive sound, im this excited about the clean sound!! The thing is too loud for me to crank at home now, so I havent really heard the overdrive too much. I had a rehearsal tonight and ran an Xotic effects BB preamp in front of it, sounded oustanding, everyone was floored.
The amp has definetly surpassed my expectations, and I think it will be plenty loud for most all of my gigs. Thanks Stephen, Zaphod, and everyone else who has helped me so far.

Awesome! Congratulations!

So did you do the ladder arrangement of resistors at the 6V6 and EL84 grids, like I showed you? And what kind of rectifier are you using?

One word of warning, if you go for the huge cathode cap trick, you need to bias the power tubes a little cooler. Like a shared 180 ohms on the EL84 pair's cathodes and 270 ohms for the 6V6 pair.

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Great tones come in small glass jars!

Great to hear. That iron was from Heyboer and is the 36 watt spec iron based on the 18 watt.com 36 watt amp derivative. The OT may have a bit more high end response so maybe that's why you're heaing a bit of hiss now.


You talk about using 6V6 & EL84 so do you have a mix of 2-EL84 & 2-6V6 running into the same OT? or have you settled on one type?

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

I am waiting on a shipment of parts, then I will do the ladder on the grids. Right now I have it set up as it was in the Trinity V6, which seems to default to the EL's and not hit the 6v6's as hard. I will heed your warning and adjust my cathode resistors as well, thanks.



I didnt really think this through as well as I could have Stephen. As you know, the chassis is punched for 2 of each kind of tube. I could get the holes enlarged, but I thought I would try running a mix of power tubes. I tell ya, it sounds absolutely beautiful, kinda reminds me of one of those old Reeses peanut butter cup commercials, two great tastes that taste good together. The thing is, I played the amp for a day as an 18 watt, with just the 6v6's, but with the 36 watt OT. The hiss was there even then too. I just hope I havent wired it wrong. Are the wire colors universal, ie, the impedances and such? I can probably live with the hiss, but it bugs me because I was so proud of how quiet the amp was before. I went around bragging every time I turned it on.....

Yeah, 6V6s and EL84s together are a great combination!


Just check that your secondary is grounded. Heyboer tends to have a standard set of colours they use for the primary and secondary connections. So I would have expected you would connect the colours the same as with the 18W transformers. Apart from that I can't see any obvious reason why you would get more hiss. Usually most hiss comes from the tubes themselves.

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Great tones come in small glass jars!

Just check that your secondary is grounded. Heyboer tends to have a standard set of colours they use for the primary and secondary connections. So I would have expected you would connect the colours the same as with the 18W transformers. Apart from that I can't see any obvious reason why you would get more hiss. Usually most hiss comes from the tubes themselves.[/quote]
How about this: The 18 watt OT had long leads, and I braided em up nice and pretty. Had em tucked against the chassis very neatly. The 36's leads had been cut, so they were just barely long enough to make it to the impedance switch. So as it is, they are not braided, and they are floating somewhat as well. You guys think this would cause some noise?? If so, I will simply add a few inches of wire to each of the leads and braid em up and tuck em away like they were........

I think it's unlikely. Apart from checking that the secondary side's grounding is secure, you could also try swapping the primary side's blue and brown wires.

But like I said, most hiss comes from tubes.

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Great tones come in small glass jars!

Zaphod said..."But like I said, most hiss comes from tubes."

Because I thought my voltages might be creeping up a bit with the SS rect, and maybe a hot bias with the big cap mod, I switched to some JJ 6v6s tubes because I hear they can take just about anything. They also sometimes cause audible hissing. I put my NOS G.E. 6v6s back in ........... Ahhhhhhh the sounds of silence.......

Interesting. so the JJ were noisy at the same voltages? You might want to go with a tube rectifier and keep the voltages lower.
What is the B+ now?

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

My recommendation was to use a sag resistor or a zener to get the B+ down to where it should be.

IMO unless the B+ is a lot above 450V, there's no need to worry about the NOS GE 6V6s. It's only the real old metal jacket or coke bottle 6V6s that have the lower tolerance to high voltages. The later regular small glass bottle 6V6s were designed for use inside TV sets and can take hits of some real high voltages.

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Great tones come in small glass jars!

Went to Lowes and bought one of those super expensive stepper drill bit things, enlarged the EZ 81 hole in about 45 seconds. I will now install an 8 pin socket, and try a GZ34. I may keep the SS as an option, I may not.

I havent checked my voltages yet today, I keep changing stuff every day lol. I will check them before and after the GZ 34 and post. I tried a few things today, and I believe I do need to get my bias down. I am waiting on those resistors. I went back to the 220ufs, and the sound improved a bit on the overdrive. Of course it lost that tight bottom.. Tells me Zaphod was right again, and my bias was indeed off. should be able to get that straight very soon.

Oh, and yes the JJ's were considerably noisier at the same voltages. They sound great, but with that particular pair, the noise floor went up quite abit. The pair in there now are.... G.E. 6v6 GT's NOS, internet buy, very cheap, from my favorite kinda unknown seller.... I have a serious tube problem BTW....

Well, the heater winding on the PT is indeed 5 volts, i have 290 volts on pins 4 and 6 of my GZ 34, 5 volts on 2 and 8...
Then my meter took a crap........ I fired it up, and it is making sound. Can't play very loud now, but its working. Hopefully all parts will arrive tomorrow, and Ive been meaning to get a decent meter anyhow. I almost took the plunge and bought a Fluke at Lowes tonight, but I decided to wait and find out exactly what I should get. Any suggestions?

Fluke. Model depends on need and wallet.
At home I use a model 21 and have since about 86. At work I use several different models. Fluke is the only meter the company buys for field use.

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Fantasy Noise is what my shop of dreams is called and was the only way to beat my addiction, like many here I suffer from G.A.S.


Tele's make the best noise

I'm not a big fan of JJs but i would let them burn for a while. Some new tubes are noisey right out of the box and quiet down after a few hours of use.

If I were to switch this amp to an all 6v6 type, what do you guys think would be the ideal plate resistor values for the 6v6's?? Obviously the current setup wont work, and due to a few other developments down the power chain, I would like to get my voltages down a bit, and my bias cooler.

What plate resistor??? IMO it would be a huge pity to change to all 6V6s, when you can get such an awesome tone by combining 6V6s and EL84s.

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Great tones come in small glass jars!

Ok, this may get kinda long so bear with me for a minute. My PT was heating up pretty bad, and it wasnt any bigger physically as my 18 watt PT, exactly the same size. I figured it was't up to the task, so I talked to the guys at Mercury. They pointed me to a Vibrolux PT with the lowest B+. Same footprint, 315-0-315, 5 volt rectifer winding, bias winding, much more laminations, everything seemed perfect. Bolted it in, wired it up with a GZ34, EL84's are redplating. Talked to s my advisor, god bless em, he gets me all freaked out about plate resistors, uneven voltage loading on the different power tubes, and I freaked out, drilled the chassis out and installed 4 6v6's. Keep in mind, my multimeter had taken a crap on me, so all I had to go on here was eyes and ears. Well today I get my Fluke in the mail, and start taking some voltages, My B+ is 325VDC?? Pin 4 of my 6v6s i have 315 VDC?? WTF?? I am soooo fricken confused at this point. Everyone is telling me different stuff, and I really don't have a clue to begin with. I just want the 6v6's and EL84s to run at a nice bias, with out my PT getting hot enough to cook on.

BTW the big Mercury PT is getting hot too!!!!

He's talking total baloney. He must be on crack. Fortunately you can get little adapter plates from Webber so you can out 9-pin sockets in an octal hole, IIRC.

If your tubes are red-plating, they may just need to be biased cooler (ie use bigger cathode resistors). Also check that all the power tube grids are at 0V, or nothing will go right. This isn't rocket science.


The OT has winding resistance which will cause some voltage drop. And if the tubes are drawing too much current, the voltage drop will be increased. That could also explain your PT overheating. Also what size of screen grid resistors are you using? If they're the traditional 18W 100 ohm ones, it might make sense to increase them to 1k.

Also I don't know what PT you were using before, but any Trinity 36W PT I've seen is considerably bigger than an 18W.

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Great tones come in small glass jars!

The problem is, I couldnt seem to get the bias low enough on the EL's. I went as far as a 250 ohm reisitor with no luck.

All that is behind me now anyhow, the amp is fixed bias now, I switched it. I couldnt stand the guess work of the cathode biasing in this situation. Everything was running very hot, although it sounded great lol.

So, now I have to wait on Mojo to send me some adaptors so I can go back to the EL 84's on 2 of the outputs. It should be much easier for me to deal with now, as I will have seperate bias pots for each pair of tubes.

I also ordered some zeners, but I'm not sure if I will need them, lets see how the day pans out

I will check on the grids.....