Update the next morning: the EL34L that vibrates when shaken is the culprit. With that out and the other three tubes in, the voltage at pin 5 is -42VDC at each socket. With that tube in, its pair goes down to -27VDC and the other side to -37VDC. The amp itself remains healthy. Whew.
I don’t suffer from anxiety, but 35 years ago I opened up my Gibson GA-35 RVT amp and broke out in a cold sweat and started hyperventilating when I saw the wiring mess inside. Looking at this Hiwatt is somewhat a very calming, Zen type feeling. That is beyond neat and well laid out. Thanks for showing it!
From the jj vendor in the NW, the El34L is recommended to have screen grid resistors of 1k or greater because of either premature failure or damage to the amp. They have very hungry screens that will draw a lot of current. I've had 5 different amplifiers come across my bench, including my own, that had screen grid resistors from 100-700 ohm up to 5 watt, all burn components or just totally fail. My own amplifier is a 2017, peavey VB-MA (sister to the VB-3), uses 8 el34 tubes, with 509v on the plates, 493v on the screens, it was biased at 55%ish with 5 watt 700 ohm ceramic screen resistors. Hooked in conventional pentode configuration fed by regulated SMPS. I had 3 fail and burn up screen resistors. My check up on it one month prior had no burning at all, and I've had it since new. Jj el34l is never a recommendation.
HiWatt went to KT77 tubes from EL34 and these were EL34 back in the day, (nothing against JJ) to deal with heat issues associated with the 100 Watt. The harder vacuum power tube was also a cleaner tube as Reeves and Joyce wanted a louder cleaner amp. I made this recommendation for a DC30 amp that was going through power, even NOS EL34…to switch to KT77, and these were JJ’s… problem solved and it worked for the band as they were a country group.
@@Renshen1957 KT77 are good tubes, amazing sound and clarity. However, per datasheet, they are only rated for a 400v max on screens in standard pentode mode. They were intended to be ran in UL configuration. I've had JJ and Russian ones fail with 425 on screens. They are just fussy on how they want to run . But i thought the later Hi-watt went to KT88 for the high clean output, not kt77?
I'm old enough to remember having the TV repair man coming to our house to fix our big B&W TV. I recall being fascinated as he tested tubes, in one case rebuilding the channel selector by hand right before my eyes, and generally the innards looked pretty similar to the clean layout this amp has. When everything was 'hand wired' ...what a time and what we have evolved into as far as tech.
I think the reason was that the customer (or someone else) replaced the former EL34's by J/J E34L's, ignoring that the latter ones need a higher, more negative bias voltage for the same plate current. Hence the tubes were run too hot for some time, causing a premature failure. The DR103 design dates back from the times of tube heyday, as any other tube powered amp. Tubes were produced more meticulously, leading to closer tolerances. Nowadays' tubes need to be biased individually, not by just the turn at one trimpot or even without any adjustment possibility at all.
This has to be the prettiest wiring on a Amp I have ever seen ,maybe he was a Competent Electrician and or A very good Electronics Technician ,I love how the wires are bent ,I used to do Automated Lighting Panels this way its clean and shows quality work very nice
My understanding is that Harry Joyce refused to compromise on workmanship for the sake of production numbers, which is why you see the attention to detail.
JJ Killer, better run, run, run, run, run, run, run away... Every right to be proud of that work Lyle! I wish people would tread as lightly on Lupe's work as you've done here with Harry's. A really great way to implement that mod.
I wonder if JJ has resolved the quality problems they've had of late? I've been avoiding them after seeing Brad get so many bad ones, they used to be among my favorites.
@@socallars3748 Of late? Back when Tesla changed to JJ I had a bunches of 6L6s and EL34s biasing weird on me. Some tubes were ice cold and the others were red plating. Yay, another bad batch!
@@Satchmoeddie Bummer. Yeah, I had a 6V6 from a matched pair red plating right out of the box...popped a pair of Electro-Harmonix in the same amp and they work fine. Happily the vendor replaced them without a fight, but I'm not too eager to order more.
Oh wow!!! So interesting to see a vintage Hiwatt on your bench like that. This is going to be an interesting series of videos. That bias board you made looks awesome too.
I love seeing the internals of old Hi Watts. Really interesting video. I'm appreciating your text overlays in the last few videos, it helps me follow along.
Hmm! I've just had the same problem with a JCM2000 that the client had furnished with a brand new set of JJ EL34s. One of them was murdering the bias for itself and its partner. First time I've had an issue with their tubes. Thanks from Durban, South Africa for another great clip!
This wasn't an early example with the bad motherboard was it? Those JCM2000's that weren't upgraded with the Revision 20 board will have bias issues. Lyle has a whole video on this problem.
You used to be able to pick these up for peanuts in the late 80s. Awesome amps but my friend's pair used to savage weak valves. I miss mine, it never gave me a minute of trouble in the years I had it.
Not the first time I have had them JJs tubes do that to the bias. I have had brand new JJs do that too me. I designed some negative Zener regulated MOSFET & PNP transistor negative voltage regulators for my PSU project, and opted to not use them after a California winder designed a 300mA bias regulation and supply transformer for me. Those were de-rated in the MOSFET department from -800 VDC to -100 to -200 VDC P ch enhancement mode FETs & they have become MOSFET variable regulated DC bias supplies. A step attenuator in place of the single adjustment pot, added to a two MOSFET positive regulator and it's now a part of a very decent power scaling circuit now. Kind of fiddly to get the bias steps adjusted to match the B+ steps, but very nice. Use a BIG heat sink on the B+ regulator! Thermally coupling the Zener diodes to the FET heat sinks made them a lot more stable too.
I can relate to the part about trouble with line voltage and having to use a variac on the days its way off. Ive had the same problem in my house built in 1953 (built by my grandfather, i bought it with my wife when he passed about a decade ago). Throughout the year our line voltage will dip as low as 98v and peak as high as 136v. And the thing that makes it so insidious is how quickly those cycles occur. For example theres been days where i would meaure 126v in the early morning hours and by noon it would be down to 106ish then back to 120v by 8 p.m. So I modified a variac (added a digital display that measures all the way to 0 volts (which was also a mod cause the display only read down to 40v stock) and up to around 240v and monitors current etc) that i run all my tube equipment through. Doing that was enough to get my output tubes in my main amp lasting another six months on average. So now all my tube amps, radios/receivers and even our old slide projector go through the variac. I just wish id started using the variac sooner lol. Got to love these old houses/neighborhoods.
I used to have a vintage DR201, the one with six EL34's. I don't remember what the plate voltage was exactly, but it was in the 700's and it had no bias trim pot.
Wow, amp porn is correct! It must be a joy to work on something laid out so beautifully, as compared to the typical Fender spaghetti. Lyle, what is the one resistor laying askew on the board, with one end not connected?
@@PsionicAudio There is a resistor on the main turret board that is perpendicular to the others, connected at one end to a turret with the other end not connected. Hard to see the colors (I'm on the wrong side of 60!) but I wanna say 1M.
@@PsionicAudio Ok, I see it now...the lead does a dogleg and connects to a turret on the same side. Like I said, old eyes! It just jumped out at me because of its orientation. One of these things is not like the others! 😁
I've never had luck with Tube Depot, frankly their product and matching sux... And for a company that charges extra to get a "low noise", "matched", etc is just bad business practice, considering that their non premium tube prices are not great. To each his own...
I have bought in the past the JJ valves in my amps and my experience after buying a lot these valves is that they are shite. I have had more of these valves shag up my amps over the years I don't use them anymore. Yes, they are cheaper than most valves but they just aren't worth the risk.
Well seven years ago I sent it out with Tube Store Preferred Series 34s. Which at the time were better than current production Mullards. And NOS can be a very expensive gamble.
biggest letdown of my guitar life.. it's like playing in a big bass amp.. headroom is enormous.. you have to crank until the windows shake until you have a wisper of overdrive..
@@jayletter5209 Every JJ ive had or inherited spits sparks and red plates. Not worth a Feck. Piss poor eastern block entity and great way to screw up an amp. My local shop buy them in bulk and has a 50% failure rate out of the box.
That's because you're getting untested or factory seconds... Out of the 3 places currently making tubes, Czech tubes have the least problems out of the 3.
Update the next morning: the EL34L that vibrates when shaken is the culprit. With that out and the other three tubes in, the voltage at pin 5 is -42VDC at each socket. With that tube in, its pair goes down to -27VDC and the other side to -37VDC.
The amp itself remains healthy. Whew.
I don’t suffer from anxiety, but 35 years ago I opened up my Gibson GA-35 RVT amp and broke out in a cold sweat and started hyperventilating when I saw the wiring mess inside. Looking at this Hiwatt is somewhat a very calming, Zen type feeling. That is beyond neat and well laid out. Thanks for showing it!
From the jj vendor in the NW, the El34L is recommended to have screen grid resistors of 1k or greater because of either premature failure or damage to the amp. They have very hungry screens that will draw a lot of current. I've had 5 different amplifiers come across my bench, including my own, that had screen grid resistors from 100-700 ohm up to 5 watt, all burn components or just totally fail.
My own amplifier is a 2017, peavey VB-MA (sister to the VB-3), uses 8 el34 tubes, with 509v on the plates, 493v on the screens, it was biased at 55%ish with 5 watt 700 ohm ceramic screen resistors. Hooked in conventional pentode configuration fed by regulated SMPS. I had 3 fail and burn up screen resistors. My check up on it one month prior had no burning at all, and I've had it since new.
Jj el34l is never a recommendation.
HiWatt went to KT77 tubes from EL34 and these were EL34 back in the day, (nothing against JJ) to deal with heat issues associated with the 100 Watt. The harder vacuum power tube was also a cleaner tube as Reeves and Joyce wanted a louder cleaner amp. I made this recommendation for a DC30 amp that was going through power, even NOS EL34…to switch to KT77, and these were JJ’s…
problem solved and it worked for the band as they were a country group.
@@jayoh13Joyce used military loom technique in some early Hiwatts and switched to PCBs before other companies.
@@Renshen1957 KT77 are good tubes, amazing sound and clarity. However, per datasheet, they are only rated for a 400v max on screens in standard pentode mode. They were intended to be ran in UL configuration. I've had JJ and Russian ones fail with 425 on screens. They are just fussy on how they want to run .
But i thought the later Hi-watt went to KT88 for the high clean output, not kt77?
I'm old enough to remember having the TV repair man coming to our house to fix our big B&W TV. I recall being fascinated as he tested tubes, in one case rebuilding the channel selector by hand right before my eyes, and generally the innards looked pretty similar to the clean layout this amp has. When everything was 'hand wired' ...what a time and what we have evolved into as far as tech.
I think the reason was that the customer (or someone else) replaced the former EL34's by J/J E34L's, ignoring that the latter ones need a higher, more negative bias voltage for the same plate current. Hence the tubes were run too hot for some time, causing a premature failure.
The DR103 design dates back from the times of tube heyday, as any other tube powered amp. Tubes were produced more meticulously, leading to closer tolerances. Nowadays' tubes need to be biased individually, not by just the turn at one trimpot or even without any adjustment possibility at all.
This has to be the prettiest wiring on a Amp I have ever seen ,maybe he was a Competent Electrician and or A very good Electronics Technician ,I love how the wires are bent ,I used to do Automated Lighting Panels this way its clean and shows quality work very nice
I was going to say the same thing. Hiwatt has a reputation for mil spec wiring but this really is beautiful.
My understanding is that Harry Joyce refused to compromise on workmanship for the sake of production numbers, which is why you see the attention to detail.
I wish the wiring in my attic was that neat! instead it is strung all over the place and makes the attic unusable.
Lyle, your content is quickly becoming my favorite of anything on TH-cam! Great stuff
For years now, I've been torn between Ted Woodford and Lyle as my favorite channel!
JJ Killer, better run, run, run, run, run, run, run away...
Every right to be proud of that work Lyle! I wish people would tread as lightly on Lupe's work as you've done here with Harry's. A really great way to implement that mod.
I wonder if JJ has resolved the quality problems they've had of late? I've been avoiding them after seeing Brad get so many bad ones, they used to be among my favorites.
@@socallars3748 Of late? Back when Tesla changed to JJ I had a bunches of 6L6s and EL34s biasing weird on me. Some tubes were ice cold and the others were red plating. Yay, another bad batch!
@@Satchmoeddie Bummer. Yeah, I had a 6V6 from a matched pair red plating right out of the box...popped a pair of Electro-Harmonix in the same amp and they work fine. Happily the vendor replaced them without a fight, but I'm not too eager to order more.
Oh wow!!! So interesting to see a vintage Hiwatt on your bench like that. This is going to be an interesting series of videos. That bias board you made looks awesome too.
I love seeing the internals of old Hi Watts. Really interesting video. I'm appreciating your text overlays in the last few videos, it helps me follow along.
Hmm! I've just had the same problem with a JCM2000 that the client had furnished with a brand new set of JJ EL34s. One of them was murdering the bias for itself and its partner. First time I've had an issue with their tubes. Thanks from Durban, South Africa for another great clip!
This wasn't an early example with the bad motherboard was it? Those JCM2000's that weren't upgraded with the Revision 20 board will have bias issues. Lyle has a whole video on this problem.
I like the way you present your videos, I never lose interest, your voice is easy on the ear, great stuff. Thank you.
always a joy peeking into old Hiwatts, cheers
That looks stunning! Can't wait to hear it!
Aloha Lyle. Hiwatt always look so well organized.
You used to be able to pick these up for peanuts in the late 80s. Awesome amps but my friend's pair used to savage weak valves. I miss mine, it never gave me a minute of trouble in the years I had it.
This confirms what a tube junkie I am, I could sit and watch those tubes all day 😂
Great video! thanks. Your work is so meticulous and neat.
This is a very cleanly wired amp, looks like WW2/Post war military grade wiring. The guy who built this actually cared.
watching glowing tubes in the dark - can my day start any better? No, he said...it's can't.
Amp porn is RIGHT...!!!
Beautiful layout.
Can't wait to hear this one 😁👍👍
Not the first time I have had them JJs tubes do that to the bias. I have had brand new JJs do that too me. I designed some negative Zener regulated MOSFET & PNP transistor negative voltage regulators for my PSU project, and opted to not use them after a California winder designed a 300mA bias regulation and supply transformer for me. Those were de-rated in the MOSFET department from -800 VDC to -100 to -200 VDC P ch enhancement mode FETs & they have become MOSFET variable regulated DC bias supplies. A step attenuator in place of the single adjustment pot, added to a two MOSFET positive regulator and it's now a part of a very decent power scaling circuit now. Kind of fiddly to get the bias steps adjusted to match the B+ steps, but very nice. Use a BIG heat sink on the B+ regulator! Thermally coupling the Zener diodes to the FET heat sinks made them a lot more stable too.
ohhh man! While I know it wouldn't, I was expecting an explosion. The voice, the tension in the delivery ... :) Anyways...
I can relate to the part about trouble with line voltage and having to use a variac on the days its way off. Ive had the same problem in my house built in 1953 (built by my grandfather, i bought it with my wife when he passed about a decade ago). Throughout the year our line voltage will dip as low as 98v and peak as high as 136v. And the thing that makes it so insidious is how quickly those cycles occur. For example theres been days where i would meaure 126v in the early morning hours and by noon it would be down to 106ish then back to 120v by 8 p.m. So I modified a variac (added a digital display that measures all the way to 0 volts (which was also a mod cause the display only read down to 40v stock) and up to around 240v and monitors current etc) that i run all my tube equipment through. Doing that was enough to get my output tubes in my main amp lasting another six months on average. So now all my tube amps, radios/receivers and even our old slide projector go through the variac. I just wish id started using the variac sooner lol. Got to love these old houses/neighborhoods.
So this is what they are talking about. Wow.
My God. It's full of stars.
I used to have a vintage DR201, the one with six EL34's. I don't remember what the plate voltage was exactly, but it was in the 700's and it had no bias trim pot.
I have only recently acquired an EL34 equipped amp (Vadis 601) and have never had any luck with JJ tubes, and it looks like I am not alone.
I am always down for some Hiwatt content. (I have 2 Custom 50's)
In this vidéo, listening to your voice, you seem exhausted. Hope you're fine. Greetings from France. You're great Guy... Take Care of yourself
He had some great spirit. Amp Porn😂
Wow, amp porn is correct! It must be a joy to work on something laid out so beautifully, as compared to the typical Fender spaghetti. Lyle, what is the one resistor laying askew on the board, with one end not connected?
I’m not sure what you’re referring toto. All the resistors are connected at each end. Maybe you mean some going to the pots or to tubes?
@@PsionicAudio There is a resistor on the main turret board that is perpendicular to the others, connected at one end to a turret with the other end not connected. Hard to see the colors (I'm on the wrong side of 60!) but I wanna say 1M.
Both ends are connected.
@@PsionicAudio Ok, I see it now...the lead does a dogleg and connects to a turret on the same side. Like I said, old eyes! It just jumped out at me because of its orientation. One of these things is not like the others! 😁
I don't understand electronics, however, doesn't that amp look SO much better than a modern PCB version.
I've never had luck with Tube Depot, frankly their product and matching sux... And for a company that charges extra to get a "low noise", "matched", etc is just bad business practice, considering that their non premium tube prices are not great.
To each his own...
I have bought in the past the JJ valves in my amps and my experience after buying a lot these valves is that they are shite. I have had more of these valves shag up my amps over the years I don't use them anymore. Yes, they are cheaper than most valves but they just aren't worth the risk.
that 3rd tube looks quite loose when you’re tapping it
Not sure why Lyle, but when I post a comment it does not accept the comment.
Can not wait to see and hear your finished results.
I don’t have any big filters up. YT has its own system but it ain’t me.
good old amp
Let me stick my nose in the air and say that a Hi-Watt should really be rocking Mullard tubes anyways.
Well seven years ago I sent it out with Tube Store Preferred Series 34s. Which at the time were better than current production Mullards.
And NOS can be a very expensive gamble.
Steel String Swinger ™️
Nice Amp 😃
Yuuup. Pure Amp Porn. My ‘75 Champ is more like an ‘80’s SITCOM 🤣🤣
Yeah, well, when I’m done it will be Macgyver…
I have no doubts
My Danelectro Twin Twelve is like a Russ Meyers film.
My 1974 West Avalon R is like a Walking Dead episode 🤣
🤪🤪🤪🤪🤪
biggest letdown of my guitar life.. it's like playing in a big bass amp.. headroom is enormous.. you have to crank until the windows shake until you have a wisper of overdrive..
CP tubes cant handle Hiwatt voltage on the screens. eh more er less. JJ's belong in the trash.
JJ 6L6's handle the 540+V screen voltage in my Ampeg V4's with ease. Their E34L's are just fine..
@@jayletter5209 Every JJ ive had or inherited spits sparks and red plates. Not worth a Feck. Piss poor eastern block entity and great way to screw up an amp. My local shop buy them in bulk and has a 50% failure rate out of the box.
That's because you're getting untested or factory seconds... Out of the 3 places currently making tubes, Czech tubes have the least problems out of the 3.
@@NoOne-sn2si *Slovak.
Harry Joyce was my serp uncle