Power Amp

[lapideusvir]

Hi Folks,

I need your advice. I´m very pleased using a preamp-valve-pedal (that is Kingsley Maiden) in front of a SS amp (D-Class).
I´d like to go further and just go with the Preamp into a Power Amp, then into several cabs (or sim).
Thought about the Fryette Power Station for using it as a Power amp, but I found it too expensive since I dont need attenuation nor silent recording etc.

Do you know other options? Just a good Power Amp (prefered with tubes).

Thanks.
Best,
lapideus

[sgosnell]

I have no personal experience, but there is a power amp for sale on the forum, form a reputable member. He could provide more information if you ask. Stewart PA100B power amp - 50WPC / 100W bridged (@8 Ohms), 1 space 1/2 rack I have no other knowledge of it.

[Hammertone]

I have no personal experience, but there is a power amp for sale on the forum, form a reputable member. He could provide more information if you ask. Stewart PA100B power amp - 50WPC / 100W bridged (@8 Ohms), 1 space 1/2 rack I have no other knowledge of it.

Some incredibly sramt forum member bought that one already.

[nevershouldhavesoldit]

I have no personal experience, but there is a power amp for sale on the forum, form a reputable member. He could provide more information if you ask. Stewart PA100B power amp - 50WPC / 100W bridged (@8 Ohms), 1 space 1/2 rack I have no other knowledge of it.

Thanks for the nice words! Stewart still makes that series - but for some reason I've never been able to find out, they dropped the 100W version and kept the 50W. These are SS, but they're great sounding power amps that I used for everything from live performance with the Crate preamp I also posted but haven't yet sold to powering my Rogers LS3/5a studio monitors. They're also bulletproof. You can see from the pics in my sale post how well mine held up for years - it still looked better than a dealer's in-store demo when I packed and sent it to its new owner the day before yesterday.

The company is still in business and quite well respected by the studios, venues etc who use their equipment. Their 50W unit is identical in size and appearance to my 100W, and it'll pump 100W into 8 Ohms when bridged. So it's more than enough for a Twin-class DIY. And driven by a tube or tube-y preamp, they sound fantastic through good speakers (at least to me). On stage, I paired mine with either a 12" Boogie Thiele EVM cab or a 12" Bag End driver in a much smaller home built cab. The downside is that the current list price for the 50W unit is $700. I'd buy one used if I wanted another - they're incredibly reliable. Just be careful not to accidentally ground the hot speaker lead(s) - like almost all SS amps of the era, that's going to damage the amp. Fear not when buying used, though - if it works fine, it is fine. It will not make any sound at all if the output has been shorted.

If I were making myself a new powered cab, I'd either build or buy a small monoblock power amp. If you're using a tube or tube-y preamp, I'd go for a SS power stage like this $200 150W Dayton unit. I even gigged with a $35 Pyle amplifier a few months ago just to see if it would do the job - and it does! The other approach I'd consider is buying a used monoblock amp like a Dyna. There are many in the 35 to 60 watt range that are small and light enough to bolt or even velcro into a speaker cabinet.

If you're really adventurous and technically inclined, you can buy some amazingly powerful class D amplifier modules for between $50 and $200 that sound great and are truly as powerful as they're claimed to be. You'd have to put it into a case and add controls, I/O etc plus a power supply. But it's the future for many of us. DISCLAIMER: dissenting posts from those clinging tightly to their Twins are welcome - but please don't be snarky about it.

[gitman]

Seymour Duncan offers two versions of a tiny and guitar-dedicated power amp , specifically designed for use with pedalboards and one larger stereo version , also meant for modelers etc.

Seymour Duncan Powerstage™ 200 | Seymour Duncan

[Hammertone]

The SD, like the Traynor Quarterhorse (discontinued), incorporates pre-amp functionality. Class D amps have made all sorts of teeny amps possible.

Another one of our esteemed members had a Hotone "Loudster" (discontinued) for sale recently. 75 watts into 4 ohms, particularly useful for those of us who may have open-back 4-ohm cabs.

If I had a preamp but need a power amp for an open-back cab, I'd velcro one of these to the floor - plenty of juice and dead simple - hey, that's exactly what I did!

[marcwhy]

Tube power amp? Try Frenzel.

[Gitterbug]

Why tube? Class D power amps reproduce faithfully whatever you feed to them. I consider 200W bass amps such as TC Electronic BAM200 and Warwick Gnome as "intelligent" power amps giving you the benefit of a 3-band eq. If your Fx/preamp cluster provides enough signal, a 100W Harley Benton power amp also does the job at a very affordable price.

[Vihar]

Look for a used Groove Tubes Dual 75.

Never mind. The OP has no clue, and found his company down the thread so it's now blind leading the blind.

[st.bede]

The Seymour Duncan Powerstage stuff is poweramp only. I had a 700. It was truly an amazing sounding poweramp.

[Cunamara]

I had a long conversation with a guy who builds high-end audiophile power amps- for years all tube, built his reputation with these. He has gone to building his own class D power amp paired with his tube front end, which he believes sounds better than tube power amps for that application. Took him a couple years to design and build a class D he was satisfied with, rather than buying ready-made. Plus class D is much less expensive to the end user than tube power amps, which has always been an expensive way to drive a speaker.

[pcjazz]

Some incredibly sramt forum member bought that one already.

Sramt?

[pcjazz]

The Seymour Duncan Powerstage stuff is poweramp only. I had a 700. It was truly an amazing sounding poweramp.

It does have a rudimentary preamp section with tone controls but functions very well as a back end for preamp pedals, and is small enough to sit on top of a Toob. I keep one as a backup (to a Milkman 100 head, which has a tube in the preamp section).

[Vihar]

Sramt?

Schramt.

[jorgemg1984]

An amp designed for guitar expects instrument level, a power amp excpects line level, which is quite a lot more gain. You might not be so pleased with that... a good flat head amp is probably a better choice than a power amp.

[gitman]

An amp designed for guitar expects instrument level, a power amp excpects line level, which is quite a lot more gain. You might not be so pleased with that... a good flat head amp is probably a better choice than a power amp.

Isn't the signal coming from the preamp on said line level ? These power amps we mentioned are specifically designed for just that purpose ....

[jorgemg1984]

Isn't the signal coming from the preamp on said line level ? These power amps we mentioned are specifically designed for just that purpose ....

I've never had the Kingsley - but I have quite a bit of experience with other preamp pedals. In general, they do reach "line level", but don't sound as good as they do in "instrument level". They can sound "cranked" or just not as satisfactory - when the amp accepts instrument level, everything works better. Less noise and a more natural sound.

Also, a complete class D amp, with an instrument level input, these days, is as cheap and light as a power amp - there's no advantage, really.

As a side note, I've played a lot trough PAs with pedal rigs and found that using a DI at the end to go trough the mixer xlr inputs ("mic level") yelds the same results. Going trough the jacks ("line level") just adds noise and a "cranked" feel to the sound that I don't like. For people who play a lot with distortion that may not be relevant, but if you're going for a 100% clean sound with an archtop, it does make a difference.

All this in my experience, others may feel differently.

[nevershouldhavesoldit]

An amp designed for guitar expects instrument level, a power amp excpects line level, which is quite a lot more gain. You might not be so pleased with that... a good flat head amp is probably a better choice than a power amp.

I think you're conflating multiple concepts into one device. The amplification stages known as preamplification amplify voltage, and those known as power amplification amplify electrical power. So voltagae is boosted even more, and current is grossly increased - watts = volts times Amperes. A peamplifier stage is designed for input in fractions of a volt, and the standard maximum output level from it at its rated distortion is called "line level" and is usually 1 to 2 volts. So most power amplification stages require an input signal in the range of one to a few volts.

An amplifier that has both voltage amplification in the input stage(s) and power amplification in the output stage(s) is calld an integrated amplifier. It works with an input signal at the low voltage coming from a guitar pickup, a microphone etc (depending on its input parameters). The amplifiers we call guitar amplifiers are integrated amps that first amplify the millivolt-level signal from a guitar to a voltage level high enough to drive the power stages. Then that signal drives the ouput devices, which drive the speaker(s). A power amplifier does not have the voltage amplification stages to bring an instrument level signal up to the voltage needed to drive its output devices.

Traditional guitar amplifiers contain one or more preamp stages ahead of the power amplification circuitry, so they work with an input signal of about 100 to 500 mV (the range of output levels between a low output single coil and a hot humbucker or active pickup). A "power amplifier" has no preamp stages and is designed to accept an input signal of 10+ times the voltage coming from a pickup. If you run a guitar directly into a power amp input, the voltage is far too low to generate much output. Whatever sound you do get will be garbled, disorted, and very quiet And if you run the output from a preamp into another preamp, the voltage far exceeds the appropriate input voltage and the output will be garbled, distorted, and excessively loud.

Mesa Boogie was one of the first to cascade preamplification stages properly matched for impedance and other operating parameters to generate the cleverly distorted signal that makes Santana sound like Santana. That loud, distorted signal we all love is the product of preamps driving preamps by design. And this distortion is very different in sound from that generated by overdriven output stages. Both are different from the distorted sound of speaker cone breakup. The moral of this story is that if you now what you're doing, you can combine voltage and amperage amplification to tailor the sound as you wish. But if you just plug one device into another randomly, you'll probably end up with a sonic mess.

Preamp pedals take the millivolt signal from a pickup and boost it to line level so it can drive output stages directly. You can only use such a device to drive a standard guitar amp through an instrument input if it either has an instrument level output or enough attenuation on the line level ouput to cut the signal to well below a volt. The maximum output level from a Strymon Iridium at rated distortion is 0 dBV, which is 1 volt into a high impedance load. Most consumer audio equipment is rated at -10 dBV, which is 0.316V into a high impedance load. And professional audio equipment (e.g. analog studio gear) uses a +4 dB reference standard, which is 1.228V into a low impedance load. So you have to match the output of your signal source with the input level and impedance at which theat stage of amplification is designed to work.

[jorgemg1984]

I think you're conflating multiple concepts into one device. The amplification stages known as preamplification amplify voltage, and those known as power amplification amplify electrical power. So voltagae is boosted even more, and current is grossly increased - watts = volts times Amperes. A peamplifier stage is designed for input in fractions of a volt, and the standard maximum output level from it at its rated distortion is called "line level" and is usually 1 to 2 volts. So most power amplification stages require an input signal in the range of one to a few volts.

An amplifier that has both voltage amplification in the input stage(s) and power amplification in the output stage(s) is calld an integrated amplifier. It works with an input signal at the low voltage coming from a guitar pickup, a microphone etc (depending on its input parameters). The amplifiers we call guitar amplifiers are integrated amps that first amplify the millivolt-level signal from a guitar to a voltage level high enough to drive the power stages. Then that signal drives the ouput devices, which drive the speaker(s). A power amplifier does not have the voltage amplification stages to bring an instrument level signal up to the voltage needed to drive its output devices.

Traditional guitar amplifiers contain one or more preamp stages ahead of the power amplification circuitry, so they work with an input signal of about 100 to 500 mV (the range of output levels between a low output single coil and a hot humbucker or active pickup). A "power amplifier" has no preamp stages and is designed to accept an input signal of 10+ times the voltage coming from a pickup. If you run a guitar directly into a power amp input, the voltage is far too low to generate much output. Whatever sound you do get will be garbled, disorted, and very quiet And if you run the output from a preamp into another preamp, the voltage far exceeds the appropriate input voltage and the output will be garbled, distorted, and excessively loud.

Mesa Boogie was one of the first to cascade preamplification stages properly matched for impedance and other operating parameters to generate the cleverly distorted signal that makes Santana sound like Santana. That loud, distorted signal we all love is the product of preamps driving preamps by design. And this distortion is very different in sound from that generated by overdriven output stages. Both are different from the distorted sound of speaker cone breakup. The moral of this story is that if you now what you're doing, you can combine voltage and amperage amplification to tailor the sound as you wish. But if you just plug one device into another randomly, you'll probably end up with a sonic mess.

Preamp pedals take the millivolt signal from a pickup and boost it to line level so it can drive output stages directly. You can only use such a device to drive a standard guitar amp through an instrument input if it either has an instrument level output or enough attenuation on the line level ouput to cut the signal to well below a volt. The maximum output level from a Strymon Iridium at rated distortion is 0 dBV, which is 1 volt into a high impedance load. Most consumer audio equipment is rated at -10 dBV, which is 0.316V into a high impedance load. And professional audio equipment (e.g. analog studio gear) uses a +4 dB reference standard, which is 1.228V into a low impedance load. So you have to match the output of your signal source with the input level and impedance at which theat stage of amplification is designed to work.

Agreed, and all great explanations. I'm not someone who knows electrónics, at all.

My point is simple: pedals like the Kingsley, despiste being called preamps, work much better in front of an integrated amp (instrument level) than a power amp (line level). Had many of these pedals, although not the Kingsley, and used them in many live gigs. Again, all IMHO.

[sgosnell]

While I've never been near one, the Kingsley website says the Maiden is suitable for going directly into a power amp. My personal preference for amplifying a guitar is a guitar amp, but my preference is not necessarily anyone else's. If the OP already has the Maiden, connecting it to a power amp should work, and the sound should be whatever the Maiden puts out.

[Vihar]

My point is simple: pedals like the Kingsley, despiste being called preamps, work much better in front of an integrated amp (instrument level) than a power amp (line level).

I thought it sounded pretty good going directly into a power amp:

[lapideusvir]

Thanks a lot for all the information!
I´m almost convinced getting a Class D Top, like the RE Luna for example. I will check out the Seymor Duncan Power Amp, too.

Best
lapideus

[jorgemg1984]

I thought it sounded pretty good going directly into a power amp:

That's a bad example for two reasons

1) that's not an archtop and that's not a clean sound.

2) it's not very clear but I've seen severy people comment online the jack inputs of the power amp used on that video are actually instrument level

[jorgemg1984]

Thanks a lot for all the information!
I´m almost convinced getting a Class D Top, like the RE Luna for example. I will check out the Seymor Duncan Power Amp, too.

Best
lapideus

I don't want to confuse you anymore, but the Luna might not be a good choice for the simple fact that I believe is more "Fender" based, so not flat frequency... Pedals like the Kingsley are meant to be used in front of "flat frequency" devices. Anyway, people on Raezers Edge should be able to inform you on this.

If I were you, besides checking some of the bass heads are already refered here, I would check the Henriksen Bud head. It's flat and has input gain and volume controls and a nice Accutroncis digital reverb (if they use the same chip they do in the amps). It should take the Kingsley very well, all you need the is a cab.

[Vihar]

That's a bad example for two reasons

1) that's not an archtop and that's not a clean sound.

2) it's not very clear but I've seen severy people comment online the jack inputs of the power amp used on that video are actually instrument level

I don't care if you have a personal checklist to compare the video to regarding things the OP never mentioned, like "archtop" or "clean sound", but if you think that up to the 0:43 mark it's not a clean sound in that video, your comments on the broad topic of electric guitar cannot be taken seriously anymore.