JMP/HBE
Well-known member
https://reverb.com/item/1739406-sol...h3QxwfoEAQYASABEgLizvD_BwE&gclsrc=aw.ds&pla=1
Haven't seen this before ...
Haven't seen this before ...
Soldano/Hiwatt hybrid ...
- Thread starter JMP/HBE
- Start date
Joey Voltage
New member
Re: Soldano/Hiwatt hybrid ...
It looks like the preamp board was gutted, and was just modified to a standard highwatt circuit for the pre, with out the beefy hiwatt power section. There’s not much slo circuitry left in it, just the logo. If mike was the one who did the work and can authenticate it, it’s one thing, but if that’s aftermarket gut job, that thing is as good as worthless.
It looks like the preamp board was gutted, and was just modified to a standard highwatt circuit for the pre, with out the beefy hiwatt power section. There’s not much slo circuitry left in it, just the logo. If mike was the one who did the work and can authenticate it, it’s one thing, but if that’s aftermarket gut job, that thing is as good as worthless.
Last edited:
GoldenVulture
Braindeadologist
JMP/HBE
Well-known member
Re: Soldano/Hiwatt hybrid ...
6L6 vs EL-34 would be obvious. Hiwatts with Partridge Trannies had plate voltages well past 500vdc.
Im guessing they're not getting 550 volts out of 5881's/6L6's.
6L6 vs EL-34 would be obvious. Hiwatts with Partridge Trannies had plate voltages well past 500vdc.
Im guessing they're not getting 550 volts out of 5881's/6L6's.
Joey Voltage
New member
Re: Soldano/Hiwatt hybrid ...
It was a completely different output topology. Hi watts used a slightly higher ht for the plates, but ran the screens at a more comfortable voltage. It’s a super reliable way to run an output section and can increase output power if you do things right, especially if you run the screens from a separate isolated supply from the plate supply (Most hiwatts didn’t go that far), and use an OT with a suitable a-a primary load.
The 5881’s mike used are sovteks, which aren’t really 5881’s, they are just a close equivalent. They are rugged as hell Russian military equivalents that were used in military servos for bomber doors, and were designed to be used in extreme weather conditions in places like Siberia. The sovtek can take up to 500 or so volts in its plates but I wouldn’t run them like that given a choice.
El34’s are rated to take up 800v on the plates, but it’s the screens you have to worry about. Most can only take a maximum of 450v on the screens, and most amps that use them exceed this, and pretty much misuse them in general. It’s one of the reasons el34’s tend to have a reputation of a quicker burn out.
It was a completely different output topology. Hi watts used a slightly higher ht for the plates, but ran the screens at a more comfortable voltage. It’s a super reliable way to run an output section and can increase output power if you do things right, especially if you run the screens from a separate isolated supply from the plate supply (Most hiwatts didn’t go that far), and use an OT with a suitable a-a primary load.
The 5881’s mike used are sovteks, which aren’t really 5881’s, they are just a close equivalent. They are rugged as hell Russian military equivalents that were used in military servos for bomber doors, and were designed to be used in extreme weather conditions in places like Siberia. The sovtek can take up to 500 or so volts in its plates but I wouldn’t run them like that given a choice.
El34’s are rated to take up 800v on the plates, but it’s the screens you have to worry about. Most can only take a maximum of 450v on the screens, and most amps that use them exceed this, and pretty much misuse them in general. It’s one of the reasons el34’s tend to have a reputation of a quicker burn out.
Last edited:
JMP/HBE
Well-known member
Re: Soldano/Hiwatt hybrid ...
6550's were used in Servo Amps in B-52's, not really an "Audio" tube but ive had a couple JMP's that had 6550's and they sounded good.
5881's were discovered in the 50's when the first Mig-15 defected to South Korea from the North.
The US had put out a cash reward for the first pilot to defect.
The Air Force thought the Mig was a "Secret Weapon" as US Pilots were getting shot down at an alarming rate.
They flew the Mig back to CIA "Area 51" and reversed Engineered it. What they found was it wasnt the Mig that was better but that US Pilots lacked Dogfighting experience. Same thing in Vietnam but the fact that the F-4 had no internal gun [until later] & that more than 50% of Air to Air Missles either didnt come off the rail or failed to track caused alot of problems.
The Air Force came up with "William Tell" & the NAVY/USMC has Top Gun. What they found is if Pilots could get 10 missions under their belt they had a huge success rate. That is the purpose of those Programs.
I was an AO onboard USS CONSTELLATION CV-64 in 81-82, during Vietnam VF-96 the Fighting Falcons "Showtime 100" F-4J Piloted by LT, Duke Cunnigham & Rio LTjg Willy Driscol became the first ACES of Vietnam.
Now back to our regularly scheduled program ...
6550's were used in Servo Amps in B-52's, not really an "Audio" tube but ive had a couple JMP's that had 6550's and they sounded good.
5881's were discovered in the 50's when the first Mig-15 defected to South Korea from the North.
The US had put out a cash reward for the first pilot to defect.
The Air Force thought the Mig was a "Secret Weapon" as US Pilots were getting shot down at an alarming rate.
They flew the Mig back to CIA "Area 51" and reversed Engineered it. What they found was it wasnt the Mig that was better but that US Pilots lacked Dogfighting experience. Same thing in Vietnam but the fact that the F-4 had no internal gun [until later] & that more than 50% of Air to Air Missles either didnt come off the rail or failed to track caused alot of problems.
The Air Force came up with "William Tell" & the NAVY/USMC has Top Gun. What they found is if Pilots could get 10 missions under their belt they had a huge success rate. That is the purpose of those Programs.
I was an AO onboard USS CONSTELLATION CV-64 in 81-82, during Vietnam VF-96 the Fighting Falcons "Showtime 100" F-4J Piloted by LT, Duke Cunnigham & Rio LTjg Willy Driscol became the first ACES of Vietnam.
Now back to our regularly scheduled program ...
Last edited:
Joey Voltage
New member
Re: Soldano/Hiwatt hybrid ...
A lot of the tubes commonly used for guitar amps weren’t designed for audio. The two most common exceptions are the el34, and el84’s. The EL34 was designed as a hifi audio valve, and the el84 was designed to be used in cheap commercial phono amplifiers. A lot of the kinkless tetrodes were designed for hi-if audio as well but aren’t too commonly used. The 6V6 I’m not too sure whether it was designed initially for audio or not.
5881’s 6l6’s etc, were all primarily military servo valves. Fender just used them because they were common and cheap.
A lot of the tubes commonly used for guitar amps weren’t designed for audio. The two most common exceptions are the el34, and el84’s. The EL34 was designed as a hifi audio valve, and the el84 was designed to be used in cheap commercial phono amplifiers. A lot of the kinkless tetrodes were designed for hi-if audio as well but aren’t too commonly used. The 6V6 I’m not too sure whether it was designed initially for audio or not.
5881’s 6l6’s etc, were all primarily military servo valves. Fender just used them because they were common and cheap.
Hot Octopus
Member
Re: Soldano/Hiwatt hybrid ...
if you've got a kemper...
https://bighairyprofiles.com/item/bhp-slowat
if you've got a kemper...
https://bighairyprofiles.com/item/bhp-slowat
Lake Placid Blues
New member
Re: Soldano/Hiwatt hybrid ...
5881 is the military part number for the 6L6GB the standard US beam tetrode tube of the 1950s. American beam tetrodes carry a alphabet subfix to indicate upgraded versions , such as 6L6A (19watts) followed by 6L6B (23 watts), 6L6C (30 watts)... 7581 is the military part number for a 6L6GC.
6L6 was originally RCA's version of a beam tetrode to compete with the British KT66. In American they were called beam tetrodes or beam power tubes. Later beam pentodes was also used to indicate they could be used in place of a pentode, but that doesn't mean they are pentodes. It either has beam forming plates or has a 5th element in the form of an suppressor grid. Not both. In England they were called Kinkless Tetrodes if it uses beam forming plates. Beam tetrodes and kinkless tetrodes are the same thing. GEC and MO Valves could not build pentodes because Philips/ Mullard held a patent on pentodes so they invented the kinkless tetrode which they shared with RCA. This was during the 1930s.
The modern Sovtec 5881 is actually equivalent to a 6L6GC.
In the photos of that Hiwatt/Soldano amp it looks like GE 6CA7s which are beam tetrodes that can be used in place of an EL34. But 6550s also look similar to 6CA7s.
5881 is the military part number for the 6L6GB the standard US beam tetrode tube of the 1950s. American beam tetrodes carry a alphabet subfix to indicate upgraded versions , such as 6L6A (19watts) followed by 6L6B (23 watts), 6L6C (30 watts)... 7581 is the military part number for a 6L6GC.
6L6 was originally RCA's version of a beam tetrode to compete with the British KT66. In American they were called beam tetrodes or beam power tubes. Later beam pentodes was also used to indicate they could be used in place of a pentode, but that doesn't mean they are pentodes. It either has beam forming plates or has a 5th element in the form of an suppressor grid. Not both. In England they were called Kinkless Tetrodes if it uses beam forming plates. Beam tetrodes and kinkless tetrodes are the same thing. GEC and MO Valves could not build pentodes because Philips/ Mullard held a patent on pentodes so they invented the kinkless tetrode which they shared with RCA. This was during the 1930s.
The modern Sovtec 5881 is actually equivalent to a 6L6GC.
In the photos of that Hiwatt/Soldano amp it looks like GE 6CA7s which are beam tetrodes that can be used in place of an EL34. But 6550s also look similar to 6CA7s.
Lake Placid Blues
New member
Joey Voltage
New member
Re: Soldano/Hiwatt hybrid ...
The 5881, or 6Π3C-E which is its real name, is only somewhat of an electrical equivalent to the 6L6gc. Every valve on the market today are only, and even sometimes loosely, electrical equivalents to what was used years ago. All this means is that the spacing, thickness and structure of their internal electrodes will allow them to be used is a similar fashion, and in place of circuits that called for the original valve. But they are all for the most part different valves. For example a jj el34 is not an el34 in the true sense, but it is enough of an electrical equivalent to be called that.
Kinkless tetrodes were an improved design from original beam tetrodes which exihibited a kink in their EI curves. So it was a little more than just nomenclature. Also no beam tetrodes are not e pentodes, however the space charge within beam forming tetrodes provides an equal or similar function to a suppressor grid. A bigger difference between the two is that a true pentode tends to have huge screen current swings.
The 5881, or 6Π3C-E which is its real name, is only somewhat of an electrical equivalent to the 6L6gc. Every valve on the market today are only, and even sometimes loosely, electrical equivalents to what was used years ago. All this means is that the spacing, thickness and structure of their internal electrodes will allow them to be used is a similar fashion, and in place of circuits that called for the original valve. But they are all for the most part different valves. For example a jj el34 is not an el34 in the true sense, but it is enough of an electrical equivalent to be called that.
Kinkless tetrodes were an improved design from original beam tetrodes which exihibited a kink in their EI curves. So it was a little more than just nomenclature. Also no beam tetrodes are not e pentodes, however the space charge within beam forming tetrodes provides an equal or similar function to a suppressor grid. A bigger difference between the two is that a true pentode tends to have huge screen current swings.
Last edited:
Empty Pockets
BadHairDayologist
Re: Soldano/Hiwatt hybrid ...
$10k for a weird hybrid amp? I think if he was around $4k he'd have sold it by now.
$10k for a weird hybrid amp? I think if he was around $4k he'd have sold it by now.
Re: Soldano/Hiwatt hybrid ...
They actually drew the wrong conclusion. It was all about "corporate culture".
USAF and Navy ran their guys like a varsity football team, all pride and testosterone... Soviets ran theirs like an Olympics team, all discipline, rigour, and ice. Strict as hell, too. They ran their guys A LOT harder to compensate for disadvantaged hardware.
You can spot an old Soviet pilot from across a large room in any country, even 30-40 years retired. They all give off this unmistakeable relaxed-formidable vibe that's laid back enough to be admirable rather than terrifying. It's like "mellow Terminator mode", always-on, 24-7.
the Mig back to CIA "Area 51" and reversed Engineered it. What they found was it wasnt the Mig that was better but that US Pilots lacked Dogfighting experience. Same thing in Vietnam but the fact that the F-4 had no internal gun [until later] & that more than 50% of Air to Air Missles either didnt come off the rail or failed to track caused alot of problems.
The Air Force came up with "William Tell" & the NAVY/USMC has Top Gun. What they found is if Pilots could get 10 missions under their belt they had a huge success rate. That is the purpose of those Programs.
I was an AO onboard USS CONSTELLATION CV-64 in 81-82, during Vietnam VF-96 the Fighting Falcons "Showtime 100" F-4J Piloted by LT, Duke Cunnigham & Rio LTjg Willy Driscol became the first ACES of Vietnam.
Now back to our regularly scheduled program ...
They actually drew the wrong conclusion. It was all about "corporate culture".
USAF and Navy ran their guys like a varsity football team, all pride and testosterone... Soviets ran theirs like an Olympics team, all discipline, rigour, and ice. Strict as hell, too. They ran their guys A LOT harder to compensate for disadvantaged hardware.
You can spot an old Soviet pilot from across a large room in any country, even 30-40 years retired. They all give off this unmistakeable relaxed-formidable vibe that's laid back enough to be admirable rather than terrifying. It's like "mellow Terminator mode", always-on, 24-7.
Last edited:
Lake Placid Blues
New member
Re: Soldano/Hiwatt hybrid ...
Have either of you two read this book?
https://www.barnesandnoble.com/p/bo...MIk6-E9_KK3QIVFcJkCh3uOQPUEAQYAiABEgLBHvD_BwE
Have either of you two read this book?
https://www.barnesandnoble.com/p/bo...MIk6-E9_KK3QIVFcJkCh3uOQPUEAQYAiABEgLBHvD_BwE
