Go Back   Christian Guitar Forum > Musicians > Amps & Effects
Register FAQ Members List Calendar Arcade Mark Forums Read

Reply
LinkBack Thread Tools Display Modes
Unread 05-14-2016, 12:35 PM   #1
Xcelerate.
 
gopats1479's Avatar
 

Joined: Sep 2010
Location: Champaign, IL
Posts: 508
12AT7 problems

So recently I've been trying to reduce the amount of gain in my HT-5R because I don't need more than probably half of the gain that's there. I'm trying tube swaps right now because that's where some online discussion has directed me. The first thing I tried was an EHX 12AU7, but with my Strat it was too low gain, so I popped the stock tube back in and kept searching for the tone I wanted. This past week, I tried a Groove Tube 12AT7 because I thought the gain factor would work better. It sounded great...until I heard the microphonics. They gave me a pretty big headache, and I took the tube back to GC the same day and exchanged it for a second, which was also microphonic. I returned it that night and went to another local store the next day to see if they could deal with the problem. I tried another GT 12AT7, and it was still a bit microphonic, though not at first sight like the other two were. I gave up at that point with trying 12AT7s.

All that being said, here's my questions:
1) Are 12AT7s more microphonic than other tube types? I haven't had a problem with any other tube types in this amp.
2) If not, could there be a problem with the way the HT-5R circuit interacts with this particular type that makes it not work?
3) Are there any other things I should try (other tube types, etc.) that might help me get more usable range out of the amp?

And please, don't suggest a new amp as the solution because right now I don't have the money and my local used gear market isn't active at all, so a trade is probably out of the question too. I don't need any more fuel to my GAS.

__________________
My blog: My Own Little World

My electric rig: Fender Deluxe Player's Strat > Morley Little Alligator > Dunlop Echoplex Preamp > Line 6 M13 > Blackstar HT-5R w/ a 5751

Other stuff: Yamaha CPX-1200 (acoustic), Mid-2000s Fender Standard Jazz Bass
gopats1479 is offline   Reply With Quote
Sponsored Links
Unread 05-14-2016, 03:37 PM   #2
Tired of being attacked
 
BillSPrestonEsq's Avatar
 

Joined: Jun 2001
Location: Beaverton, Or
Posts: 40,448
I have heard a lot of complaints of 12at7s in v1. I have heard more people liking 5751s in place of a 12ax7. Myself, I prefer just turning down a 12ax7.

But maybe a 5751 will get you where you want to go. I also kind of like some microphonics in my lower gain tones.
__________________
For this I will be judged.


My Life.
BillSPrestonEsq is offline   Reply With Quote
Unread 05-14-2016, 06:02 PM   #3
Registered User
 
Iron Broadsword's Avatar
 

Joined: Feb 2013
Posts: 138
IMHO 5751's are the way to go because it won't change the tone on you too bad. I've not tried one personally, but I do know that the other 12A__ types all sound like junk in a 12ax7 slot. 5751 seems the way to go.
Iron Broadsword is offline   Reply With Quote
Unread 05-14-2016, 08:12 PM   #4
Xcelerate.
 
gopats1479's Avatar
 

Joined: Sep 2010
Location: Champaign, IL
Posts: 508
Funny that you both mention the 5751 because after doing some more reading on the Blackstar forums, I decided to call down to my favorite local store and see if they had any in stock. They didn't, so I placed a special order for a Sovtek one, and it'll be coming in about a week or so.

My entire purpose in this, in case it wasn't clear, is to make a larger portion of the gain knob usable so that I can dial in a more precise tone. So yes, Bill, I could just turn down the gain with my 12AX7, but when I'm below 9:00 on that gain knob things get really quiet really fast. I want to be able to have a little more room to work with in that gain range.
__________________
My blog: My Own Little World

My electric rig: Fender Deluxe Player's Strat > Morley Little Alligator > Dunlop Echoplex Preamp > Line 6 M13 > Blackstar HT-5R w/ a 5751

Other stuff: Yamaha CPX-1200 (acoustic), Mid-2000s Fender Standard Jazz Bass
gopats1479 is offline   Reply With Quote
Unread 05-15-2016, 02:03 PM   #5
Registered User
 
Iron Broadsword's Avatar
 

Joined: Feb 2013
Posts: 138
Yeah I figured, a lot of guys end up with an amp they wish had less gain for the same reasons. Usually though the amps that have gain that far beyond what you're looking for are also voiced to sound like something you don't want with low gain though. I'm sure you know what you want, but just saying the numbers are slanted that way it seems.
Iron Broadsword is offline   Reply With Quote
Unread 05-15-2016, 03:39 PM   #6
Tired of being attacked
 
BillSPrestonEsq's Avatar
 

Joined: Jun 2001
Location: Beaverton, Or
Posts: 40,448
Quote:
Originally Posted by Iron Broadsword View Post
Yeah I figured, a lot of guys end up with an amp they wish had less gain for the same reasons. Usually though the amps that have gain that far beyond what you're looking for are also voiced to sound like something you don't want with low gain though. I'm sure you know what you want, but just saying the numbers are slanted that way it seems.
I agree. But I am generally looking for more gain...
__________________
For this I will be judged.


My Life.
BillSPrestonEsq is offline   Reply With Quote
Unread 05-15-2016, 09:43 PM   #7
Xcelerate.
 
gopats1479's Avatar
 

Joined: Sep 2010
Location: Champaign, IL
Posts: 508
Quote:
Originally Posted by Iron Broadsword View Post
Yeah I figured, a lot of guys end up with an amp they wish had less gain for the same reasons. Usually though the amps that have gain that far beyond what you're looking for are also voiced to sound like something you don't want with low gain though. I'm sure you know what you want, but just saying the numbers are slanted that way it seems.
Very true, but I like the tone I'm coaxing out of it more. I just need more fine adjustment in my case. The HT-5 has this really interesting on-the-edge-of-breakup tone that I've never really tried to get before that I am loving at the moment.
__________________
My blog: My Own Little World

My electric rig: Fender Deluxe Player's Strat > Morley Little Alligator > Dunlop Echoplex Preamp > Line 6 M13 > Blackstar HT-5R w/ a 5751

Other stuff: Yamaha CPX-1200 (acoustic), Mid-2000s Fender Standard Jazz Bass
gopats1479 is offline   Reply With Quote
Unread 05-16-2016, 04:29 AM   #8
Registered User
 
Iron Broadsword's Avatar
 

Joined: Feb 2013
Posts: 138
As an alternative or while you're waiting for the tube in the mail, ever try running your guitar volume at half? If you don't have a treble bleed cap it will get dark, but the gain will certainly decrease by a lot. Treble bleed cap is a must if you wanna do this, but this is how I run my class 5 and it's really a beautiful setup. Crank guitar volume to 10 for a solo, 7 for crunch, 5 for pristine clean.
Iron Broadsword is offline   Reply With Quote
Unread 05-16-2016, 08:17 AM   #9
Your Ad Here
 
Stratopastor's Avatar
 

Joined: Oct 2004
Location: NE England
Posts: 789
I don't understand why 12AT7s are microphonic in this application but, regarding gain issues, I do think you need to keep in mind that all these valves are dual triodes. In this amp one half of the valve feeds the other half, so any gain reduction is squared; if a 12AX7 is nominally 100, your 12AU7 (nominally 20) will give you one-fifth of one-fifth the gain you had before. In other words, not a lot.

5751 (nominally 70) is probably a good idea. I use a 12AY7 (nominally 40) in the front end of my Fender amp, which also feeds V1a into V1b. EH make them.
__________________
But godliness with contentment is great gain (1 Tim 6:6)
Stratopastor is offline   Reply With Quote
Unread 05-16-2016, 10:33 AM   #10
Xcelerate.
 
gopats1479's Avatar
 

Joined: Sep 2010
Location: Champaign, IL
Posts: 508
Quote:
Originally Posted by Iron Broadsword View Post
As an alternative or while you're waiting for the tube in the mail, ever try running your guitar volume at half? If you don't have a treble bleed cap it will get dark, but the gain will certainly decrease by a lot. Treble bleed cap is a must if you wanna do this, but this is how I run my class 5 and it's really a beautiful setup. Crank guitar volume to 10 for a solo, 7 for crunch, 5 for pristine clean.
I used to do this without a treble bleed and enjoyed it until I started playing with different tones from my amp. The problem with it for me was my tone got too hairy when I raised the volume because I dialed in my amp for like 5 on my guitar's volume. I'd rather have my basic mid-gain tone be with my guitar volume at 10 and turn it down to 6 and add in my Echoplex for cleans.
__________________
My blog: My Own Little World

My electric rig: Fender Deluxe Player's Strat > Morley Little Alligator > Dunlop Echoplex Preamp > Line 6 M13 > Blackstar HT-5R w/ a 5751

Other stuff: Yamaha CPX-1200 (acoustic), Mid-2000s Fender Standard Jazz Bass
gopats1479 is offline   Reply With Quote
Unread 06-27-2016, 08:06 AM   #11
Xcelerate.
 
gopats1479's Avatar
 

Joined: Sep 2010
Location: Champaign, IL
Posts: 508
Long overdue update, but the 5751 had problems getting to my store because EHX/Sovtek was having shipping issues. I put it in my HT-5 last week and began tweaking my settings like crazy. I've now ended up with only using the drive channel for everything with my guitar volume typically set around 6 or 7 with the tube comp model in my M13. The gain is about 9:00 and my amp's volume is typically around noon. I put the Echoplex on when I need overdrive and can also dime my guitar's output if I need even more.

In short, I'm loving what it's done. It is a hair microphonic on max volume, but I never run anywhere close to there, so I think I'll be OK. I used it leading from electric at church yesterday, and I have never been more satisfied with my live tone. It just works incredibly well for what I'm going for.
__________________
My blog: My Own Little World

My electric rig: Fender Deluxe Player's Strat > Morley Little Alligator > Dunlop Echoplex Preamp > Line 6 M13 > Blackstar HT-5R w/ a 5751

Other stuff: Yamaha CPX-1200 (acoustic), Mid-2000s Fender Standard Jazz Bass
gopats1479 is offline   Reply With Quote
Unread 06-27-2016, 10:52 AM   #12
...
Administrator
 
thesteve's Avatar
 

Joined: Apr 2001
Location: San Diego, CA
Posts: 30,106
Send a message via AIM to thesteve
Very cool. Glad it worked out.
__________________
We've all got ideas. We are the music makers. We make money to buy things, and write down words.

I'm a podcaster
thesteve is offline   Reply With Quote
Unread 06-27-2016, 01:51 PM   #13
Your Ad Here
 
Stratopastor's Avatar
 

Joined: Oct 2004
Location: NE England
Posts: 789
Good-oh.
__________________
But godliness with contentment is great gain (1 Tim 6:6)
Stratopastor is offline   Reply With Quote
Reply

Tags
12at7, blackstar, ht-5, tube

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 08:06 AM.


Search Engine Friendly URLs by vBSEO 3.6.0 PL2