Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Ed_Chambley on October 09, 2019, 05:11:54 am
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I have spent numerous hours with low efficiency speakers, 6v6 and smaller tubes. 2 output in push pull, 2 and 3 tubes SE, I have tried a few 9 pins. A lot of the common tubes. The closest I have gotten to a big tube tone is using 4, 6v6 in push pull and even 2 6v6 and 2 EL84. I tried 1 6L6 in push pull with 2 EL84 and sounded great, but 28 watts.
So, What amp 15 watts and less have you found to get a big amp tone.
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HI: I built a Marshall super lead using 4 el90/6aq5 and get big tone... I thinks its somewhere around 15 -20 watts?
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So, What amp 15 watts and less have you found to get a big amp tone.
On a recording, (not as much live) I think the 6BM8 and ECL84 tubes have a great bass response & good mids and can provide a big amp , IMO.
IF you use a Hughes & Kettner "Red Box" and run an amp thru a PA system, you can get a big tone. I've been listening to the amp (see attached schematic) almost weekly in a band setting for over 4 yrs. Big tone, IMO. The band has used all kinds of instruments: harp, mandolin, banjo, piano, electric keyboard, flute, harmonica, etc...… that would compete with the electric guitar and the guitar still cuts thru the mix quite well.
With respect, Tubenit
* while the schematic shows 6K6 tubes, the owner of the amp usually uses JJ 6V6's but has used NOS 6K6's also.
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6aq5 sounds great in push pull. Supposed to be a 7 pin 6v6 but they sound smoother and more round to me. Maybe it's the circuit I built. Also rca 6973 sounds huge to me, in between an el84 and 6L6 to my ears. But there are a ton of unknown smaller tubes. I love the tone of this se 6G6g with an ef86 preamp tube and half of a 12ax7 in parallel followed by the second 12ax7 gain stage. Really like 6F6gt ubes they sound similar to a 6V6 but cleaner and nice high end.i hear a 6F6g with the coke bottle shape sound great so want to try a pair in a 6v6 pp circuit. To me 6v6 have more mid range bite. 6K6 is similar to a 6F6gt but less balls. Experiment you can get good used
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are you mixing metaphors? you want feedback on ONLY small bottle low watt? Cuz I like BIG bottle low watt.
4SE EL84 into a 4 speaker Marshall cab sounded best big sound little bottle.
KT 88 sweating into a 2X 12 hand picked speakers for big bottle low watts
both amps ~~ 20W self biased
2 EL34's PP self biased into either cab got there but it clocked in ~ 30W
the pre signal conditioning seems to be rather important to the "bigness"
The one "constant" negative from guitar owners, my builds are hard to get guitar feedback at distance. which I attribute to low watts
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my solution just use big tube & rebias. if it stresses the trannies so much the better. if it breaks, rebuild. works for vintage tone.
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> hard to get guitar feedback at distance. which I attribute to low watts
You don't need Power to get feedback. Hearing aids will feed-back fine. You need GAIN.
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You need GAIN.
thanks for clarification,
I still ain't using AX7's :icon_biggrin:
the last amp I did do the Vin Vout math at max, near squared wave; Vgain = 105
that does get my head itching;
if I can drive the PA with a near square wave n the PA is near/at clipping, is there any more gain to be had? :dontknow:
thanks
dave
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Gain of a normal guitar amp BELOW clipping is more like 20V/20mV or a thousand.
If you won't use hi-gain tubes, use more low-gain tubes. Three sections of 12AU7 is more gain than two sections of 12AX7.
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:laugh:
as I was watching my lawnmower belt fly out of the deck, my brain said 105 gain seems odd :laugh:
the # is in to speaker, at pre out it's 580 n ya 3 gain stages outputting ~75vac rms into the 88, biased at 40v.
back to ED,
the "loudest" fullest amps in your 15w that I've fixed n heard
Gibson GA8 pSE 6v6
tweaked up 5E3 PP 6v6 jj's
Ampeg SET converted to bigger OTs and 6V6
all 3 played through 2 X 12's ~~ 100db spl
As Jeff said, mike_d for big venue or death metal drummers
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ed, build a low B+ powered EL34 AB1 with cathode bias. sounds 100% better than EL84s any day, in any way. very dynamic for low wattage amp when used with SS rectifiers. another option is 300V B+ 7591 - 20ish watts but hey, use the same damn EL84 PS and a deluxe 6.6K OT. :BangHead: you're in 60's ampeg country there.
--pete
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build a low B+ powered EL34 AB1 with cathode bias. sounds 100% better
+10
my "gold standard" amp is just that - plexi-type pre.
had 6 gigging musicians over 3 days play through it, NONE would believe me when I said it's 23W, they ALL swore it HAD to be 40W; musicians :think1:
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What PS xformer are yall using for the low watt EL34 amp?
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I had a WPT100 doing nothing so I used it
Used an OT for a Marshall 100W :think1:
Used a IT for a Gibson :w2:
all for 23W of GREAT audio :icon_biggrin:
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What PS xformer are yall using for the low watt EL34 amp?
https://www.edcorusa.com/xpwr152 (https://www.edcorusa.com/xpwr152)
the link below for more B+ (350-ish V).
https://www.edcorusa.com/xpwr050 (https://www.edcorusa.com/xpwr050)
you can push the 6.3V secondary to well over 4A without concern.
--pete
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Thx fellows, will check these Xformers out!
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fwiw
the 2nd PT Pete listed is one I use for about anything small bottle n it's so small n cute :icon_biggrin:
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Thanks everyone. I had the opportunity to play a gig a few weeks ago and the place was open air. A Beer Brewery by a large river. I normally use 2 amps Wet/Dry.
Same old set list, with about half country and half Rock. I used a Super Lead and a Super Reverb. There was plenty of space, so no one got their ears killed. Bass Player, P Bass and a 72 Ampeg SVT.
I haven't played amps like these without isolation in years. I felt like throwing all my little tube amps away.
And yes, a EL34 SE amp sounds much better to me too. It was 4 of those in the super lead I am sure that made a huge difference. Plus I was using Altec 417, which are 93 spl and my Super was running effects and cleans. I could not find a weak note on the neck anywhere. Great Fun!
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A Beer Brewery by a large river.
Currahee Brewing Company?
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.... I used a Super Lead and a Super Reverb. There was plenty of space, so no one got their ears killed. Bass Player, P Bass and a 72 Ampeg SVT.
I haven't played amps like these without isolation in years. I felt like throwing all my little tube amps away.
Yes! :l2:
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A Beer Brewery by a large river.
Currahee Brewing Company?
No, but I have played there. Small place, but nice and by the Little Tennessee River. No, this is New Belgium Brewery in Asheville. Huge place by the French Broad River. https://www.newbelgium.com/brewery/asheville/
This place has big outside stage and have open house 2 Saturdays a month.