Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on January 11, 2023, 08:48:42 am
-
plate voltage will be 400V
-
plate voltage will be 400V
Yes, but 1750N or 1750P would be a better choice.
-
thanks. i dont have those. i have only these OT's. Should i run 6L6's instead?
-
thanks. i dont have those. i have only these OT's. Should i run 6L6's instead?
Yes. Hammond says the 1760J is their replacement for a Bandmaster. I used the 1760J on this amp...
http://sluckeyamps.com/phoenix/phoenix.pdf
-
outstanding work!
-
I've used the 1760J with 6L6GC, 5881 and KT66 with really nice results, but I think Sluckey's suggestions is better when using EL34s.
/Max
-
are these safe to buy? are they really JJ's?
https://www.ebay.com/itm/185439260429?hash=item2b2d0a8f0d%3Ag%3AHyMAAOSw4X5ijN28&amdata=enc%3AAQAHAAAA4EBwAtHpP8kEDD0UQKwGGkNkQTwLjtQQWJjEbk%2FZkw9lvfz9dwqJ0fOAHqVwuALkfjPNxrTwIHCOyx7BAxMbPSGjwupNJ8UZlo0Jm94lPgHcaLNq6tblNlSwhEj0zc6ETqSu5S%2BJvBf89Q%2BiSDce5tDdwQEZlgdWhPM0oLonwOr%2B65LtUIfs1SreHPX%2BG4jjl5VfXzW1ngcEdNm3X6%2B9%2FuUz9HVSi2kv9wlE5q%2B6DNrXFyO2G%2FGmRguj2a6B1paswAx2Nh0o3PlvhOaEEaQRXKMEMu%2BfAC2XSzq8dRMWnC3R%7Ctkp%3ABk9SR-Cq05i0YQ&LH_ItemCondition=1000 (https://www.ebay.com/itm/185439260429?hash=item2b2d0a8f0d%3Ag%3AHyMAAOSw4X5ijN28&amdata=enc%3AAQAHAAAA4EBwAtHpP8kEDD0UQKwGGkNkQTwLjtQQWJjEbk%2FZkw9lvfz9dwqJ0fOAHqVwuALkfjPNxrTwIHCOyx7BAxMbPSGjwupNJ8UZlo0Jm94lPgHcaLNq6tblNlSwhEj0zc6ETqSu5S%2BJvBf89Q%2BiSDce5tDdwQEZlgdWhPM0oLonwOr%2B65LtUIfs1SreHPX%2BG4jjl5VfXzW1ngcEdNm3X6%2B9%2FuUz9HVSi2kv9wlE5q%2B6DNrXFyO2G%2FGmRguj2a6B1paswAx2Nh0o3PlvhOaEEaQRXKMEMu%2BfAC2XSzq8dRMWnC3R%7Ctkp%3ABk9SR-Cq05i0YQ&LH_ItemCondition=1000)
-
All my JJ tubes have that red JJ logo printed on the tube.
-
Well the getter does not look like what I've seen on JJ's.
That said, you are only seeing one tube in this "quad." The seller has taken one photo of a tube, and then photo-shopped a quad (or a pair as seen in another listing).
I would not trust this. But, truth is, you never really know until the item arrives.
My personal mantra is to buy from companies you know, or, if the bargain is too good to resist (meaning: the price factors in the risk of a crap product).
-
plate voltage will be 400V
Depending on how stiff that 400V and how strong the EL34, heavy overdrive could result in a short life for a 40W OT, even though its impedance is a fraction over ideal.
-
Going with 6L6's. I am just realizing certain power tubes really wanna see the right impedance at the OT. EL34 and 6L6 not really interchangeable
-
thanks. i dont have those. i have only these OT's. Should i run 6L6's instead?
Yes. Hammond says the 1760J is their replacement for a Bandmaster. I used the 1760J on this amp...
http://sluckeyamps.com/phoenix/phoenix.pdf
The phoenix looks like a fun amp to build/play. I like the Ampeg/Fender combination.
-
I bought an Ampeg Gemini II new in '68. Wish I still had it. And I've had several AB763 Fenders through the years. Yes, the Phoenix was fun to build and play. Did you see my build page? I put all that in a 12.5 x 6.5 chassis that I had previously built a Plexi 6V6.
-
Depending on what type of amp you're building I'd wanna recommend the Tungsol 5881, since your running on pretty low B+ voltages. I think those sound really nice allround.
/Max
-
Going with 6L6's. I am just realizing certain power tubes really wanna see the right impedance at the OT. EL34 and 6L6 not really interchangeable
Heater and screen grid current draws are the key hurdles to interchangability.
If you’re not optimising for max power output, EL34 should be absolutely fine with 4k and a 400V HT.
People seem to be tied into a misconception that EL34 can only be used with a 3k4 OT.
Whereas whether a load is appropriate depends on the HT supply and design goals, eg see https://tubedata.altanatubes.com.br/sheets/010/e/EL34.pdf
-
Thanks yes i'm aware of filament constraints. With this PT i have plenty filament supply as it is a marshall 100 watt PT so it will be fine powering either. the HT will likely deliver 425VDC after rectification i forget what it had before i pulled it but i know it was over 400vdc
-
Why would you use a 100watt PT with a 40watt OT???
-
using two OT. stereo poweramp project.
-
Oh yeah. I can't keep up. Wouldn't it be nice to keep all this discussion in the same thread?
-
I bought an Ampeg Gemini II new in '68. Wish I still had it. And I've had several AB763 Fenders through the years. Yes, the Phoenix was fun to build and play. Did you see my build page? I put all that in a 12.5 x 6.5 chassis that I had previously built a Plexi 6V6.
I have not seen the build page for this amp. Can you point to a link? I have visited your page before, but I don't remember how I got there.
-
Oh yeah. I can't keep up. Wouldn't it be nice to keep all this discussion in the same thread?
That's what they do in Antique Radio Forum (ARF).
One Radio one Thread.
-
I have not seen the build page for this amp. Can you point to a link? I have visited your page before, but I don't remember how I got there.
http://sluckeyamps.com/index.htm
-
I have not seen the build page for this amp. Can you point to a link? I have visited your page before, but I don't remember how I got there.
http://sluckeyamps.com/index.htm
Thanks! Bookmarked