Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on May 23, 2010, 06:31:38 am
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HI Guys, Just thinking out loud here and have a few questions. Can anyone give me an approx. wattage of the HOSO 56?If it is about 10W would a single 5881 be approx. similar? Do both require PI's. Which would be better suited to very clean to very NASTY. What is the Valve (usually 12ax7) directly after the preamp valve refered to as? Does this valve add any extra gain to the preamp valve. Is a preamp Valve (12ax7, EF86 ,5879 and one more if any knows of another that has a unique sound) able to be confiqued to be very clean as well as very nasty?
Here is what i am thinking:- 12ax7
Single Input } EF86 }12ax7 } Tonestack} PI }EL84 Single
5879 EL84 Or 5881
?????
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HoSo56 with EL84's about 18w. With 6V6's maybe 14w? With 6BM8's about 7-9w. I built all three of those. They all sounded good to me.
Based on DaGeezer's experiments with Mat's mini-HRM single ended amp into 5881's ............ I do NOT think you will ever
come close to the HoSo56 tone with a single ended design. I advise building it as a push/pull with the power tube of your choice.
With respect, Tubenit
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You don't require a PI with a single ended amp.
You may be refering to the cathode follower (CF), typically used to lower impedance and drive a tone stack.
Although it may not sound like a HOSO 56, it still may be a great little amp to try.
5879 } Gain Pot } 12AX7/CF } Tone Stack } Volume } Power tube (EL84, 6V6, 6L6, etc)
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Although it may not sound like a HOSO 56, it still may be a great little amp to try.
5879 } Gain Pot } 12AX7/CF } Tone Stack } Volume } Power tube (EL84, 6V6, 6L6, etc)
I've built this but using an EF86 instead of the 5879 w/ an El84 output tube. I was originally going for an AC-4 then the Heritage version came out and then I modified a bunch of things and this was the final outcome. I have switches for pentode/triode for the EF86, it has a variable feedback for adjustable gain, there's a CF cathode bypass switch and then the tone stack can be bypassed for more gain, mids, and tweed tones w/ a final switch on the EL84 for negative feedback. It's a rockin' little amp that's fun and very versitile.
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Hi Guys Thanks for the info. Jojokeo i would like to here more about some of the tweaks you have done to your amp. I think when i was thinking outloud i may have lost a bit in translation. So a schem was created.what i would like to be able to have some of the unique sounding small amps that can be played from CLEAN to VERY MEAN!!!.But someone may need to help me with the plate voltages and mods to be able to crank it past MAX . Thanks
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I'm building something like that in a Marshall 18 watt chassis from Webervst. But just 2 channels.
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Hi Guys Thanks for the info. Jojokeo i would like to here more about some of the tweaks you have done to your amp. I think when i was thinking outloud i may have lost a bit in translation. So a schem was created.what i would like to be able to have some of the unique sounding small amps that can be played from CLEAN to VERY MEAN!!!.But someone may need to help me with the plate voltages and mods to be able to crank it past MAX . Thanks
Is that what you are planning to build - a four headed monster? :grin:
I bet you would only play two of them for the most part the way I can see it - wait, I actually can't see it. :laugh: It needs to be a little bigger but I get the idea. I'm not sure what exactly you're talking about but pentodes are fun tubes to play with. Maybe bypass caps, or making them adjustable instead or multi switched pots, pentode/triode, screen & biasing fun, etc...? You just have to take the time to play around a bit and find things you like. Let me know if there's something specific you need, maybe I can help?
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Hi jojokeo, You are close in calling it a four headed monster. The idea for this build was generated from my last build, MY OPUS . The EF86 preamp was from Vox AC15, which sounds great with a les paul jr.I had also heard great things about fender champs having fun mods.Hoso 56 also getting great wraps, with the minicat as a wildcard to makeup the forth head. I donot play in a band, this is just a way of getting some different sounds in one box ( or in this case it will all be in a head)I only have bedroom size room to cram all my stuff in. I have two other builds 50w and 30w so the next need only be about 10w. My technical knowledge is not great ,so i require some assistance when it comes to the minimum and maximum of compontant values to change the output of a valve ( other words what do you have to do to a valve to make it clean or scream???) TO make it worse i am thinking of adding another power valve (EL84 with its own O/T ) to be able to switch to another sound. THANKS