I love you, man!!! I have been working six days a week for the past few months (saving up for that promised Apple M2 Pro rack-mount coming next year), and haven't been able to hang with you everyday like I did during the peak of the pandemic nightmare. I absolutely love your extreme attention to detail! I have learned so much from you over the past three years!!! I will never be a tech, but now I know how to know if a tech is the real deal!!! Anything less than you, and . . . peace out! You need to have a paid university where you teach the next generation of amp techs to keep the genius quality of your work alive!
The original SVTs are a pleasure to work on compared to the new ones. I always wanted to get new PCBs made out of FR4 material for the power tube Driver board as that phenolic PCB is a weak point in the amp. The Heat really does a number on that board... Also, replacing the CC screen resistors helps a lot...
I have a mid-ish 70's v4b, it's interesting how similar, yet different it is to the bigger brother SVT inside and out... The 6K11 tube scared me at first, then I found they were still pretty easily found and not a "premium" price, so I picked up a couple NOS RCA spares :) I was glad to see at least JJ is making 7027 power tubes for them still too!
7199s, 12BH7s, 6CG7s/6FQ7s, 6C10s, 6K11s, 6U10s, 7591s, 6146Bs, 7027As, 6DR7s, 12DW7s, and what other valve oddities did Ampeg use? 6CS7s? I have most of those tubes. I am out of good 7199s. I got stung on 3 sleeves of NOS RCAs. They were genuine new old stock RCAs with clean straight virgin pins & perfect ink but they were also 85% junk in the original 1970s red RCA block letter boxes. I think the tubes were rebranded Korean or Indian made tubes.
I have Mexican made RCAs too. 6BM8s with little Mexican eagles etched on the glass from RCA's Mexico factory. No esta bueno. RCA's Brazilian factory did decent work. Mexico? Not so much. RCA moved an American factory to Mexico in the 60s or 70s to save money on labor. The Brazilian factory was quite old and they really knew their business. The Mexicans & Koreans never really got the hang of it. India made some junk tubes too.
You forgot to mention the 7868! I had a Jet J12D from the middle to late sixties that used those for output instead of 7591's. I've never tried any of the repro 7199's and have heard mixed mixed comments about the quality or lack thereof. As you probably know, 7199's can be substituted with 6EA8, 6GH8 or 6U8 tubes *if you rewire the sockets* which unfortunately isn't so easy to do on amplifiers such as Ampegs built with the tube sockets soldered directly to the circuit boards. I have been meaning to make myself some adapters for such scenarios. I have pretty much all of the tubes you mention, except 7199's.... And yes, towards the end, RCA was importing all kinds of tubes from other countries and rebranding and relabeling them. Sadly, they didn't stick to using imported Mullards!
@@Satchmoeddie , "Uncle Ned" Carlson at Triode Electronics has written about when they were buying tubes in bulk from National (Richardson) in the well known red and white boxes; they might be Chinese or Indian junk and they might turn out to be Mullard or Telefunken or some other high quality European make. Pretty much the same scenario when IEC became IEC Servicemaster and went to the pale blue and white boxes, most of that stuff was absolute crap.
@@Satchmoeddie , I don't know if I've ever seen any Mexican made tubes; perhaps some Los Gatos tubes I once had, with a ssnarling cat or panther on the boxes, might have been Mexican. I don't really remember.
Magnatone also used lots of oddball tubes such as 12DW7 (7247), 6DR7, 6973, 6CZ5, 6GW8 (ECL86) etc. I've seen late model Scott hifi tuners with 6C10 or 6K11/6BK11s. Although I've never seen a piece of equipment that actually used them, in my collection I have several *10-pin* tubes, the 6AF9 and 6T9 if I remember correctly. One of these types has 10 pins in a concentric semi-circle and the other one has the standard 9 pin arrangement but with a 10th center pin in the middle of the tube base!
A quick blurb on the wacky-ist place (in circuit) to put a standby switch on a tube amp might seem apropos, relating to this...and every other Ampeg/Oliver "monstrosity" (maybe WAY too nerdy a topic). Should I design shielding for it? Unless you are running an amp design that somehow requires it, why is a standby switch even relevant in amps?...vis a vis, my Oliver P-500 has zero preamp section cathode bias(bypass) caps, by design (like an Ampeg!), and is noisy as shit at idle (like and Ampeg!). (and/or) My standby switch is in the front of my "head", directly adjacent to my tone stack...to save space (in the most compact amp design of 1970)...damn you, Jess Oliver!
Running high-voltage, whether AC or DC (especially AC) up to the front of the amp, near to or directly passing by the preamp and tone circuits, is always something to be avoided if possible. An old trick I've seen in plenty of vintage Hifi amplifiers is to use a tightly coiled, long, small diameter spring, clamped or soldered to the chassis, as a sort of conduit pipe for the high voltage wires (be aware that some spring steel alloys can't be soldered to). Working on old vintage stereo gear, I sometimes see annoying scenarios such as the wires to the power switch being run right next to one channel's preamp tube and therefore you would have more hum on one channel than the other. Relocating those wires the long way around, tucked in against the side of the chassis and away from the preamp, usually fixed the problem. Another annoying scenario that is sometimes seen in small guitar amps as well as old hifi gear is when the volume or tone control has an AC on-off switch mounted to the back of the control. This is a sure-fire recipe for inducing hum into the audio signal. Take those wires off of the switch and relocate them away from the preamp; and if you don't want to drill a hole into the chassis to install an on-off switch in a location that is away from the preamp circuitry, then put a switch on the power cord itself or use a separate switchable power strip to turn it on and off.
Very hard to beat the sound of this hi-fi bass amp. That said, it is expensive to own, with 8 output tubes needing balancing. Buying matched quads is so expensive it would be nuts to not beta match an individual replacement when needed.
Appears to be a Warehouse 12" speaker model. From their website: "The ET65's creamy lows blend with tight midrange and sparkling highs for some of the best tones ever created. This speaker is for classic rock, country, and blues. Upgrade from your Celestion™ G12-65."
Iron… Rusting… Well I never, I for one am shocked. Previous tech must’ve been a total hack (Or a thief wanting to put a new one in to sell or use the vintage one) if he thought surface rust would affect a transformers function, it’d have to be really, really extreme to affect anything.
It is the best amp I have ever played through. Literally mind blowing.
Call me jealous. I love the SVT amps. Good Lord willing I'll have another someday!!
I think that was "how many more times" by Zepplen but I'm not sure it's the name of the song. Then Ramble on was the last one.
I love you, man!!! I have been working six days a week for the past few months (saving up for that promised Apple M2 Pro rack-mount coming next year), and haven't been able to hang with you everyday like I did during the peak of the pandemic nightmare. I absolutely love your extreme attention to detail! I have learned so much from you over the past three years!!! I will never be a tech, but now I know how to know if a tech is the real deal!!! Anything less than you, and . . . peace out! You need to have a paid university where you teach the next generation of amp techs to keep the genius quality of your work alive!
Great info
All that's missing now is a couple of 8x10 cabinets... bass bliss...
Love that little bit of Zep at the end there. Sweet.
Love the clean work. Can see solder gobs that bounce off and burn in. Rare for some but always assume it's there.
The original SVTs are a pleasure to work on compared to the new ones. I always wanted to get new PCBs made out of FR4 material for the power tube Driver board as that phenolic PCB is a weak point in the amp. The Heat really does a number on that board... Also, replacing the CC screen resistors helps a lot...
Sound pretty clean!
Very promising, and great progress! Do you take requests? A little Whipping Post from this beast would be a blast... ;)
Cool.
Your client knows😎👍
I have a mid-ish 70's v4b, it's interesting how similar, yet different it is to the bigger brother SVT inside and out... The 6K11 tube scared me at first, then I found they were still pretty easily found and not a "premium" price, so I picked up a couple NOS RCA spares :) I was glad to see at least JJ is making 7027 power tubes for them still too!
7199s, 12BH7s, 6CG7s/6FQ7s, 6C10s, 6K11s, 6U10s, 7591s, 6146Bs, 7027As, 6DR7s, 12DW7s, and what other valve oddities did Ampeg use? 6CS7s? I have most of those tubes. I am out of good 7199s. I got stung on 3 sleeves of NOS RCAs. They were genuine new old stock RCAs with clean straight virgin pins & perfect ink but they were also 85% junk in the original 1970s red RCA block letter boxes. I think the tubes were rebranded Korean or Indian made tubes.
I have Mexican made RCAs too. 6BM8s with little Mexican eagles etched on the glass from RCA's Mexico factory. No esta bueno. RCA's Brazilian factory did decent work. Mexico? Not so much. RCA moved an American factory to Mexico in the 60s or 70s to save money on labor. The Brazilian factory was quite old and they really knew their business. The Mexicans & Koreans never really got the hang of it. India made some junk tubes too.
You forgot to mention the 7868! I had a Jet J12D from the middle to late sixties that used those for output instead of 7591's. I've never tried any of the repro 7199's and have heard mixed mixed comments about the quality or lack thereof. As you probably know, 7199's can be substituted with 6EA8, 6GH8 or 6U8 tubes *if you rewire the sockets* which unfortunately isn't so easy to do on amplifiers such as Ampegs built with the tube sockets soldered directly to the circuit boards. I have been meaning to make myself some adapters for such scenarios. I have pretty much all of the tubes you mention, except 7199's.... And yes, towards the end, RCA was importing all kinds of tubes from other countries and rebranding and relabeling them. Sadly, they didn't stick to using imported Mullards!
@@Satchmoeddie , "Uncle Ned" Carlson at Triode Electronics has written about when they were buying tubes in bulk from National (Richardson) in the well known red and white boxes; they might be Chinese or Indian junk and they might turn out to be Mullard or Telefunken or some other high quality European make. Pretty much the same scenario when IEC became IEC Servicemaster and went to the pale blue and white boxes, most of that stuff was absolute crap.
@@Satchmoeddie , I don't know if I've ever seen any Mexican made tubes; perhaps some Los Gatos tubes I once had, with a ssnarling cat or panther on the boxes, might have been Mexican. I don't really remember.
Magnatone also used lots of oddball tubes such as 12DW7 (7247), 6DR7, 6973, 6CZ5, 6GW8 (ECL86) etc. I've seen late model Scott hifi tuners with 6C10 or 6K11/6BK11s.
Although I've never seen a piece of equipment that actually used them, in my collection I have several *10-pin* tubes, the 6AF9 and 6T9 if I remember correctly. One of these types has 10 pins in a concentric semi-circle and the other one has the standard 9 pin arrangement but with a 10th center pin in the middle of the tube base!
Its on its way to glorious low frequencies :)
Nice jam at the end ,,my lighter is in the air bro lol
Classic amp. Deserves the works. 😁
Agreed... there has never been a "bad" era SVT. Some not as good as others... but never a "bad" one. Even the solid state output ones...
A quick blurb on the wacky-ist place (in circuit) to put a standby switch on a tube amp might seem apropos, relating to this...and every other Ampeg/Oliver "monstrosity" (maybe WAY too nerdy a topic). Should I design shielding for it? Unless you are running an amp design that somehow requires it, why is a standby switch even relevant in amps?...vis a vis, my Oliver P-500 has zero preamp section cathode bias(bypass) caps, by design (like an Ampeg!), and is noisy as shit at idle (like and Ampeg!). (and/or) My standby switch is in the front of my "head", directly adjacent to my tone stack...to save space (in the most compact amp design of 1970)...damn you, Jess Oliver!
Running high-voltage, whether AC or DC (especially AC) up to the front of the amp, near to or directly passing by the preamp and tone circuits, is always something to be avoided if possible. An old trick I've seen in plenty of vintage Hifi amplifiers is to use a tightly coiled, long, small diameter spring, clamped or soldered to the chassis, as a sort of conduit pipe for the high voltage wires (be aware that some spring steel alloys can't be soldered to). Working on old vintage stereo gear, I sometimes see annoying scenarios such as the wires to the power switch being run right next to one channel's preamp tube and therefore you would have more hum on one channel than the other. Relocating those wires the long way around, tucked in against the side of the chassis and away from the preamp, usually fixed the problem. Another annoying scenario that is sometimes seen in small guitar amps as well as old hifi gear is when the volume or tone control has an AC on-off switch mounted to the back of the control. This is a sure-fire recipe for inducing hum into the audio signal. Take those wires off of the switch and relocate them away from the preamp; and if you don't want to drill a hole into the chassis to install an on-off switch in a location that is away from the preamp circuitry, then put a switch on the power cord itself or use a separate switchable power strip to turn it on and off.
Used to have one, should have never ever sold it😔
Much better
Any love for Deoxit D100 for improving contacts?
Very hard to beat the sound of this hi-fi bass amp. That said, it is expensive to own, with 8 output tubes needing balancing. Buying matched quads is so expensive it would be nuts to not beta match an individual replacement when needed.
Can somebody give me an opinion if a 1979-1984 top boost ac30 made in England is a good vintage amp to consider. Thanks
Not really. Bad years.
ET65?
Appears to be a Warehouse 12" speaker model. From their website: "The ET65's creamy lows blend with tight midrange and sparkling highs for some of the best tones ever created. This speaker is for classic rock, country, and blues. Upgrade from your Celestion™ G12-65."
Iron… Rusting… Well I never, I for one am shocked. Previous tech must’ve been a total hack (Or a thief wanting to put a new one in to sell or use the vintage one) if he thought surface rust would affect a transformers function, it’d have to be really, really extreme to affect anything.
The more oxidation on the transformer the better the "tone". I have actually heard people say that.
Now I know what happened to my toothbrush.
You can have it back.