Hey Gingertube and Adamus,
I really enjoy the JJ ECC803S soundwise but like all JJs products they are very inconsistent. You couldn´t do without your AVO if wanting to go JJ
.
Speaking of Australian plants I bought a stash of Australian made NOS Tungsram ECL86 at eBay about a year ago. I use them as reverbdrivers in our guitar-amps. Also planning a miniature PP Schade-feedbacked poweramp that differs somewhat from the "BH".
Gingertube: Do you know anything about the Tungsram factory?
I really enjoy the JJ ECC803S soundwise but like all JJs products they are very inconsistent. You couldn´t do without your AVO if wanting to go JJ
.Speaking of Australian plants I bought a stash of Australian made NOS Tungsram ECL86 at eBay about a year ago. I use them as reverbdrivers in our guitar-amps. Also planning a miniature PP Schade-feedbacked poweramp that differs somewhat from the "BH".
Gingertube: Do you know anything about the Tungsram factory?
Lars,
I think they were probably re-badged. A lot of Tungsram stuff was.
My knowledge is incomplete but I know of only two valve manufacturing plants in Australia (there may have been more).
The Philips Hendon Factory, Alberton (a suburb of Adelaide) South Australia. - Tubes had a factory code of "PDA" on them.
The AWV Factory in Sydney, tubes had a factory code of "SDA" on them.
So if your ECL86 have either of these codes you know where they came from - otherwise I have no idea. I've maybe a dozen of Australian made ones on the shelf but labeled 6GW8. I'll have a look when I get home to see what the factory code on them is.
Keep us informed of your progress with the ECL86 Power Amp - They are a fantastic tube. Why the modern production "powers that be" (PTB's) decided to re-make the ECL82 (6BM8) instead of the ECL86 I'll never know.
As far as guitar amp reverb drivers go I prefer push pull 12AT7 an idea "borrowed" from Kevin O'Connor.
Cheers,
Ian
I think they were probably re-badged. A lot of Tungsram stuff was.
My knowledge is incomplete but I know of only two valve manufacturing plants in Australia (there may have been more).
The Philips Hendon Factory, Alberton (a suburb of Adelaide) South Australia. - Tubes had a factory code of "PDA" on them.
The AWV Factory in Sydney, tubes had a factory code of "SDA" on them.
So if your ECL86 have either of these codes you know where they came from - otherwise I have no idea. I've maybe a dozen of Australian made ones on the shelf but labeled 6GW8. I'll have a look when I get home to see what the factory code on them is.
Keep us informed of your progress with the ECL86 Power Amp - They are a fantastic tube. Why the modern production "powers that be" (PTB's) decided to re-make the ECL82 (6BM8) instead of the ECL86 I'll never know.
As far as guitar amp reverb drivers go I prefer push pull 12AT7 an idea "borrowed" from Kevin O'Connor.
Cheers,
Ian
hope i am not being thick here, but is this tthe right interpretation for gingertubes mods?
An externally hosted image should be here but it was not working when we last tested it.
I have the original "original" ECL86 BH but without UL taps on the O/P trafo so I guess I can't try this mod? However, my trafo has 8 ohm & 16 ohm taps on the secondary & I have some vague recollection of these taps being used in a pseudo UL mode - anybody know this usage & would it be applicable here?
Yes - almost right. Take the feedback connections (the ends of teh 10K resistors) to the other side of the EL84 screen resistors - that is, to the ultralinear taps themselves.
- I've got the original Baby Huey wired like this running the HiFi System at the moment.
That is because the the later fixed biased monoblock versions are on the bench having the 12AX7 twin triode diff amp front end replaced with a 2 off 6BR7 pentode diff amp - just too see how it sounds.
Cheers,
Ian
- I've got the original Baby Huey wired like this running the HiFi System at the moment.
That is because the the later fixed biased monoblock versions are on the bench having the 12AX7 twin triode diff amp front end replaced with a 2 off 6BR7 pentode diff amp - just too see how it sounds.
Cheers,
Ian
Hi Ian,
Now you are on the right track if going for plate to plate feedback. The 6BR7/EF86 might be a little wimpy though
. Better to go for a E180F or E280F. You could also go for a cascoded ECC88 as it has about the same chracteristics as a pentode.
I used EF86 as input tube in my guitaramps earlier. They are now ECC88........
Adamus,
Just live with it. EL84 tolerate over voltage very well in fact some guitar amp folks run them up over 400 volts (but with 2K2 screen resistors).
My fixed bias monoblocks are running at +350V without any signs (sounds!!) of stress.
Lars,
Without changing the BH scheme I'm limited with the current I can draw through the front end diff amp to around 600uA to 700uA maximum per side. Changing the feedback taps from the anodes (via 47K) to the Ultralinear taps (via 10K) actually helps a little here. I can draw a little more current. The 6BR7 happened to be something I picked up a batch off cheap and the (knowledgeable) supplier claims they are better than EF86. I certainly have some premium grade E180F on the shelf as well, they are used, ex a Hewlett Packard Pulse Generator, but measure 100% on the AVO MKIII. Will look at some plate curves to see if they might be better, keeping in mind my operating current limitations. Thanks for the suggestion. Work on this is "on-hold" while I repair (and part rebuild) some JADIS JA80 Mono blocks for a local chap. I want to keep the basic BH scheme. Triode diff amp limitations and all it seriously leaves all the amps I've compared against (the JADIS, Amplifons etc.) for dead, by comparison they all seem to "dumb down" the music compared to the BH.
Cheers,
Ian
Just live with it. EL84 tolerate over voltage very well in fact some guitar amp folks run them up over 400 volts (but with 2K2 screen resistors).
My fixed bias monoblocks are running at +350V without any signs (sounds!!) of stress.
Lars,
Without changing the BH scheme I'm limited with the current I can draw through the front end diff amp to around 600uA to 700uA maximum per side. Changing the feedback taps from the anodes (via 47K) to the Ultralinear taps (via 10K) actually helps a little here. I can draw a little more current. The 6BR7 happened to be something I picked up a batch off cheap and the (knowledgeable) supplier claims they are better than EF86. I certainly have some premium grade E180F on the shelf as well, they are used, ex a Hewlett Packard Pulse Generator, but measure 100% on the AVO MKIII. Will look at some plate curves to see if they might be better, keeping in mind my operating current limitations. Thanks for the suggestion. Work on this is "on-hold" while I repair (and part rebuild) some JADIS JA80 Mono blocks for a local chap. I want to keep the basic BH scheme. Triode diff amp limitations and all it seriously leaves all the amps I've compared against (the JADIS, Amplifons etc.) for dead, by comparison they all seem to "dumb down" the music compared to the BH.
Cheers,
Ian
Why not try 6973's They sound better and will take more abuse(designed for jukebox duty) 24 watts max PP
Here is the pdf.
http://www.pmillett.com/tubedata/HB-3/Receiving_Tubes_Part_2/6973.PDF:D
Here is the pdf.
http://www.pmillett.com/tubedata/HB-3/Receiving_Tubes_Part_2/6973.PDF:D
Hi Ian,
Ive decided after a long hard think to make your first Baby Huey design (with feedback alterations) my first build, mainly because of the detailed help that has already been given on the build.
So I am comprising a parts list etc, and am interested on your thoughts about OP transformers. I am just looking at some Sowter OPTs; whats your opinion on having a cheaper 2 channel transformer compared to a having one per channel? Obviously there is a big price difference, but is the performance that much more noticeable?
Cheers mate
Charlie
Ive decided after a long hard think to make your first Baby Huey design (with feedback alterations) my first build, mainly because of the detailed help that has already been given on the build.
So I am comprising a parts list etc, and am interested on your thoughts about OP transformers. I am just looking at some Sowter OPTs; whats your opinion on having a cheaper 2 channel transformer compared to a having one per channel? Obviously there is a big price difference, but is the performance that much more noticeable?
Cheers mate
Charlie
Charlie,
The baby Huey was designed specifically to work well with cheaper output transformers. It works very well with Hammond 1608 and similar. Having said that, like any other tube amp the better the output transformer the better the sound of the final product. I'm not a fan of the 2 channel output transformers, they always appear that they have been designed down to a size and price rather than designed up to a standard. If you go with Sowter then the U064 would be fine. I don't believe it would be worth the (1/2 again) extra price for the UA23 BUT it would certainly be a little better, particularly in the bottom end.
Cheers,
Ian
The baby Huey was designed specifically to work well with cheaper output transformers. It works very well with Hammond 1608 and similar. Having said that, like any other tube amp the better the output transformer the better the sound of the final product. I'm not a fan of the 2 channel output transformers, they always appear that they have been designed down to a size and price rather than designed up to a standard. If you go with Sowter then the U064 would be fine. I don't believe it would be worth the (1/2 again) extra price for the UA23 BUT it would certainly be a little better, particularly in the bottom end.
Cheers,
Ian
No worries Charlie,
The basic Baby Huey (at the risk breaking an arm trying to pat my own back) is a damn good amplifier. I do repair work for a lot of the local HiFi Tube Nutters and see some weird and wonderful amps from time to time.
Recently I have worked on a Dynaco ST70, a Chinese Music Angel 845 SET Amp, a Polish? Amplifon WL25 and some French JADIS JA80 Monoblocks. It doesn't go quite as loud as some of those but it kicks their butts sound wise.
I think you should be happy with a BH.
Cheers,
Ian
The basic Baby Huey (at the risk breaking an arm trying to pat my own back) is a damn good amplifier. I do repair work for a lot of the local HiFi Tube Nutters and see some weird and wonderful amps from time to time.
Recently I have worked on a Dynaco ST70, a Chinese Music Angel 845 SET Amp, a Polish? Amplifon WL25 and some French JADIS JA80 Monoblocks. It doesn't go quite as loud as some of those but it kicks their butts sound wise.
I think you should be happy with a BH.
Cheers,
Ian
Great thread, this!
I'm seriously considering building the "bub" and have a parochial question.
Hammond seems to be the common choice for power trafo. Now, their universal transformers are configured for 115 or 230 Volts, right? For those of us in Australia our AC is specified at 230V+/_ x% which in practice means I always get 240-250V from the wall.
Doesn't this mean all the secondaries on the Hammond will be above their rated voltage? In particular I'm concerned about the heater windings. Can anyone from Oz tell me what voltage a Hammond universal has on it's 6.3V secondaries? Or tell me why I'm concerned about nothing?
Rod
I'm seriously considering building the "bub" and have a parochial question.
Hammond seems to be the common choice for power trafo. Now, their universal transformers are configured for 115 or 230 Volts, right? For those of us in Australia our AC is specified at 230V+/_ x% which in practice means I always get 240-250V from the wall.
Doesn't this mean all the secondaries on the Hammond will be above their rated voltage? In particular I'm concerned about the heater windings. Can anyone from Oz tell me what voltage a Hammond universal has on it's 6.3V secondaries? Or tell me why I'm concerned about nothing?
Rod
Rod,
Hammond 300 Series which is what we use here in Oz has tapped dual 0 - 100, 110, 120 primaries such that they can be wired for 100, 110, 120, 200, 210, 220, 230, 240 Volts. Wire it for 240V and you won't have any problems. I've used quite a few Hammond 300 Series Power Transformers for various projects.
Cheers,
Ian
Hammond 300 Series which is what we use here in Oz has tapped dual 0 - 100, 110, 120 primaries such that they can be wired for 100, 110, 120, 200, 210, 220, 230, 240 Volts. Wire it for 240V and you won't have any problems. I've used quite a few Hammond 300 Series Power Transformers for various projects.
Cheers,
Ian
Thanks Ian.
I'm working out exactly what I need for the build (fixed bias version) and have a few basic questions. I've built a few valve circuits but don't have much experience with the SS stuff. I mean, all the bits are so SMALL
Anyway, the pots: 100R and 50k. Single or multi turn? Cermet?
The 12AX7 gridstoppers (1k5): I've got plenty of 1k, do they need to be that bit bigger?
The 2u2 cap. between the 50k pots: An 'audiophile' 400v polyprop type? A mylar?
Rod
I'm working out exactly what I need for the build (fixed bias version) and have a few basic questions. I've built a few valve circuits but don't have much experience with the SS stuff. I mean, all the bits are so SMALL
Anyway, the pots: 100R and 50k. Single or multi turn? Cermet?
The 12AX7 gridstoppers (1k5): I've got plenty of 1k, do they need to be that bit bigger?
The 2u2 cap. between the 50k pots: An 'audiophile' 400v polyprop type? A mylar?
Rod