Hi Guys
Hybrid amps of any sort can be made to sound as good as one wants, provided you do not skimp on the low-level circuitry. In the tube-pre SS-PA you have to first decide upon the tones required. If it is, say a Fender clean and Marshall distortion, that is easy. The most common mistake is to think that just copying those circuits into the box will achieve the sound.
Those iconic tones depend also on the tube power amp. Compression is not an issue until you are pushing towards full power. What matters in the icons is that each of the ectra tube stages in the PA adds a veil of tube character at ALL signal levels. So, it would seem appropriate to just add another preamp tube to acquire similar veils of character before going into the solid-state PA.
Assuming the extra tube is two stages cascaded with an attenuator between them, it is best to have a level control at the input and output of this block to allow the player the greatest control over the final sound. In this way, using iconic preamps or something more versatile like the London Power Standard preamp with clean and dirty sounds, will sound like they do when going through a tube PA. No need for compression.Where the icons plus extra block requires four tubes, the LPSP plus extra block only requires three tubes.
Have fun
Kevin O'Connor
The fact is that each veil of tube character is very much like adding extremely mild compression with each stage as the harmonic buildup is both of THD and IM, so the sound gets fatter towards the final stage.
Hybrid amps of any sort can be made to sound as good as one wants, provided you do not skimp on the low-level circuitry. In the tube-pre SS-PA you have to first decide upon the tones required. If it is, say a Fender clean and Marshall distortion, that is easy. The most common mistake is to think that just copying those circuits into the box will achieve the sound.
Those iconic tones depend also on the tube power amp. Compression is not an issue until you are pushing towards full power. What matters in the icons is that each of the ectra tube stages in the PA adds a veil of tube character at ALL signal levels. So, it would seem appropriate to just add another preamp tube to acquire similar veils of character before going into the solid-state PA.
Assuming the extra tube is two stages cascaded with an attenuator between them, it is best to have a level control at the input and output of this block to allow the player the greatest control over the final sound. In this way, using iconic preamps or something more versatile like the London Power Standard preamp with clean and dirty sounds, will sound like they do when going through a tube PA. No need for compression.Where the icons plus extra block requires four tubes, the LPSP plus extra block only requires three tubes.
Have fun
Kevin O'Connor
The fact is that each veil of tube character is very much like adding extremely mild compression with each stage as the harmonic buildup is both of THD and IM, so the sound gets fatter towards the final stage.
imho...the reverse will even be better, tube power amp and ss preamp.....guitar tube amp qualities are developed at the output stage and the output transformers i am inclined to believe....
Hi Guys
It is a fallacy promoted by Aspen Pitman to sell power tubes that the output stage is where all the tube tone is. Complete marketing BS!
As I stated above, every tube stage adds a veil of tube character to the sound - except for followers. At low loudness levels you can hear the different in tone between 12AX7 and 12AT7, and between 6V6 and 6L6. There does not have to be outright audible distortion happening.
All opinions are correct and whatever effects, distortion, tube, solidstate order you find that works for you is completely okay as long as you are not blowing up gear all the time. The preamp is the least expensive area to play with tubes and provides the greatest range of options for tone. My Studio guitar amp originally had but one preamp control and six power amp controls, demonstrating the flexibilities lirking within the PA. But most players want familiar controls, although the Studio's are now widely copied and familiar to many.
Have fun
Kevin O'Connor
londonpower.com
It is a fallacy promoted by Aspen Pitman to sell power tubes that the output stage is where all the tube tone is. Complete marketing BS!
As I stated above, every tube stage adds a veil of tube character to the sound - except for followers. At low loudness levels you can hear the different in tone between 12AX7 and 12AT7, and between 6V6 and 6L6. There does not have to be outright audible distortion happening.
All opinions are correct and whatever effects, distortion, tube, solidstate order you find that works for you is completely okay as long as you are not blowing up gear all the time. The preamp is the least expensive area to play with tubes and provides the greatest range of options for tone. My Studio guitar amp originally had but one preamp control and six power amp controls, demonstrating the flexibilities lirking within the PA. But most players want familiar controls, although the Studio's are now widely copied and familiar to many.
Have fun
Kevin O'Connor
londonpower.com
Power amps are definitely where the tube tone is- if you have your amp on 11, where it usually should be for best results. Kinda loud though!
I can't believe I used a solid state power amp (with tube pre, all in the amp) for years and years- strangely it sounded a lot better on 11 too... loud though.
My own experience/experiments with tube pres and power amps is that I really can't use the overdriven preamp, so I have that clean clean clean and the power amp is flat out, doing a wonderful synergistic thing with just the right speaker.
Not news.
Even a clean tube preamp adds a lot of lovely harmonics to the sound.
But if you have all this gear, why are you asking instead of just trying it?
I can't believe I used a solid state power amp (with tube pre, all in the amp) for years and years- strangely it sounded a lot better on 11 too... loud though.
My own experience/experiments with tube pres and power amps is that I really can't use the overdriven preamp, so I have that clean clean clean and the power amp is flat out, doing a wonderful synergistic thing with just the right speaker.
Not news.
Even a clean tube preamp adds a lot of lovely harmonics to the sound.
But if you have all this gear, why are you asking instead of just trying it?
Volume pot is ok but it might be advantageous to use the pot with a larger resistor in series to knock down the voltage into a range that the power amp will like. This will allow you to use more of the pot's rotation rather than only the bottom part of it.
Forget the transformer, I misread your post.
I just played around with a dual pentode preamp, lower than normal voltage, 40-60V. Much richer than a triode with a supply of 100-150V. Maybe all this power tube distortion lust is really pentode tube lust? Fed it into a SS 20W amp and the thing rocked.
Maybe not all this power tube distortion lust is, but certainly some of it is pentode tube distortion lust..
..and Push-Pull pentode distortion lust. Your statement rings true (!)
So why not do a tube preamp with a small tube power amp output? Overdrive the .... out of it and then send it out to your SS amp.
Anything you do to add enough harmonics so the guitar doesn't sound like "6 steel strings stretched across a plank" is going to work. There's certainly no right or wrong, and I'm not sure there's a "best", either. There are quite a few options between the aforementioned Champ and a Sword of Satori.
I do think the secret of many of the boutique amps is tweaking every stage so each adds a little distortion. Implementations that seek to get it all done in one place usually sound relatively crude.
I do think the secret of many of the boutique amps is tweaking every stage so each adds a little distortion. Implementations that seek to get it all done in one place usually sound relatively crude.
I thought that the case also but you hear more on people up sizing OT's rather than going the other direction, tried the saturated transformer thing, it did not sound all that musical.
Be kind, please resize.http://www.diyaudio.com/forums/everything-else/183084-pictures-why-not-attach-them.html
Image above fixed.
Through high school I played on the weekends in bands and then went on the road for a couple of years after. I shunned SS amps back then, even when playing bass. I had always built my amps or bought Fenders and rebuilt them to my liking. Along the line I bought a Southwest Tech (remember them?) Tigersaurus amp for a sound system project. The chassis it came in wasn't road worthy, so I mounted it into a 19” rack mountable metal chassis.
I didn't play for several years, then took it up part time again in late 1979. I built a rack mount tube preamp with switchable clean and dirty channels and ran it into the Southwest Tech SS amp. What a great setup it was. With about 200 watts available, I never pushed the power amp into distortion. I think that is the key to using SS power amps. I had a 50 tube power amp that I used sometimes for practicing and smaller gigs, but frankly, I liked the SS amp better.
If you think about it, your sound ends up going through sound system SS power amps anyway. What's the difference?
I didn't play for several years, then took it up part time again in late 1979. I built a rack mount tube preamp with switchable clean and dirty channels and ran it into the Southwest Tech SS amp. What a great setup it was. With about 200 watts available, I never pushed the power amp into distortion. I think that is the key to using SS power amps. I had a 50 tube power amp that I used sometimes for practicing and smaller gigs, but frankly, I liked the SS amp better.
If you think about it, your sound ends up going through sound system SS power amps anyway. What's the difference?
Hi Guys
The simplest way to mimic tube sound without tubes is to use jfets as gain elements. They add a fair amount of THD, and cascading two or more stages with tone shaping in between is far less expensive than an op-amp compressor. BJTs can be used similarly but tend to be more linear even when you don't want them to be.
Randall amps use a three stage fet pre and have a "not bad" sound. How close anything like this sounds to tubes is up to the individual. If it is just a preamp and you want tube tone, then a tube is the easiest way to go. Just make sure that it is doing the work of gain. Many use the tube as a follower, or in an SRPP stage or some hybrid thing with a jfet cascode and mosfet output but none of these "sound" like a tube. They are just marketing. Of course, if it works for you....
Have fun
Kevin O'Connor
londonpower.com
The simplest way to mimic tube sound without tubes is to use jfets as gain elements. They add a fair amount of THD, and cascading two or more stages with tone shaping in between is far less expensive than an op-amp compressor. BJTs can be used similarly but tend to be more linear even when you don't want them to be.
Randall amps use a three stage fet pre and have a "not bad" sound. How close anything like this sounds to tubes is up to the individual. If it is just a preamp and you want tube tone, then a tube is the easiest way to go. Just make sure that it is doing the work of gain. Many use the tube as a follower, or in an SRPP stage or some hybrid thing with a jfet cascode and mosfet output but none of these "sound" like a tube. They are just marketing. Of course, if it works for you....
Have fun
Kevin O'Connor
londonpower.com
I think that a good benefit of building this tube preamp is that it can be done relatively simply.As result it will at least enhance the SS power amp sound. Also, there is nothing wrong with taking that same tube preamp and try driving another complete tube amp with this preamp. This has been done by many artists (who can afford multiple tube amp heads).. they run the preamp-out from one tube amp head into the input of another tube amp head. Or sometimes with a two channel amp you run ch1 preamp-out back into channel 2 input
In my experience just adding an SRPP valve front end doesnt give a rich valve type sound. I found it soounded to clean.
You really need more than one stage and maybe the addded distortion of an output transformer to really get there.
http://www.ckp-railways.talktalk.net\1600watthybrid.jpg
You really need more than one stage and maybe the addded distortion of an output transformer to really get there.
http://www.ckp-railways.talktalk.net\1600watthybrid.jpg
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