Finished the 300b into a chassis today. This completes the DHT Triode 'Holy-Grail' for me - 2A3 & 300b.
Thank you George
sunil,
Nice work! Let us know which cup of the grail tastes better!
Finally finished up my 300B TSE-II build:
OTs are Electraprint 5k:8/4 gapped for 65mA. The Hammond 273BX PT puts the B+ at about 385v with my ~122v supply, and I am running the Shuguang 300B-Z Treasures at 65mA. The PT, like all the Hammond PTs I've tried so far, had quite a buzz to it, so I potted it with some of thermally conductive epoxy. I'm running the Triad choke and a DC link polypropylene deal for the supplemental power supply cap. Coupling caps are just CD 942C series. Chassis is from the fine gentlemen at Landfall Systems, transformer covers from Ebay.
I don't have the equipment to do frequency response or spectrum analysis (yet), but the square waves look great and it sounds great too, especially as these Shuguang's break in.
Thank you George!
OTs are Electraprint 5k:8/4 gapped for 65mA. The Hammond 273BX PT puts the B+ at about 385v with my ~122v supply, and I am running the Shuguang 300B-Z Treasures at 65mA. The PT, like all the Hammond PTs I've tried so far, had quite a buzz to it, so I potted it with some of thermally conductive epoxy. I'm running the Triad choke and a DC link polypropylene deal for the supplemental power supply cap. Coupling caps are just CD 942C series. Chassis is from the fine gentlemen at Landfall Systems, transformer covers from Ebay.
I don't have the equipment to do frequency response or spectrum analysis (yet), but the square waves look great and it sounds great too, especially as these Shuguang's break in.
Thank you George!
Nice work robgobson. I have a layout similar to yours but the trafos are a little more widely spaced apart. The 300b is a superb sounding tube. Enjoy !
Finally my first tube build, Tubelab SSE, is playing and the sound is very pleasing and fun. Switch at volume knob can bypass pot for external. Just now playing with EL34 but thinking of switching to 6L6 later. Base is good, mid’s are pleasing and highs are smooth. Perhaps I could test to let base go through F4 for more distinct base. Top cover getting 38°C after hours.
It has been good learning to build this. Thanks for all help here.
Tips and ideas for improvement are welcome.
——————
Power: Hammond 374BX(375-0-375), transformer input at 240V
Wall socket: 235V
Choke 193L 5H(57Ω and 100Ω in serial)
B+ 420V
C1 47uF
D3,D4, TR1 in place
Pot 50k
Tubes: GZ34, Tung-Sol 12AT7W, TAD EL34 at 53mA alt. 6L6
Output: LL2769 (4k7 8Ω)
Speakers 102dB 15” and horns
It has been good learning to build this. Thanks for all help here.
Tips and ideas for improvement are welcome.
——————
Power: Hammond 374BX(375-0-375), transformer input at 240V
Wall socket: 235V
Choke 193L 5H(57Ω and 100Ω in serial)
B+ 420V
C1 47uF
D3,D4, TR1 in place
Pot 50k
Tubes: GZ34, Tung-Sol 12AT7W, TAD EL34 at 53mA alt. 6L6
Output: LL2769 (4k7 8Ω)
Speakers 102dB 15” and horns
Attachments
Nice looking build sov
What did you think of Triode/UL and Valve /SS power supply ? I've got Altecs (~96dB) and initially thought Triode sounded so-so. With highish voltage and biased ~ 60ma, they sound nice with 807 (Brimar), 5933 (Brimar) and 6L6WB (G.E), around 360-390v.
I haven't got good sound with EL34 for some strange reason, upto 410v in my setup. Tried Mullards XF2/3 & RTF.
Thanks sunil
I have only longterm experience with one tube amp before, VSi60, which was to strong for my speakers. This one I think is way better.
My OPT can not do UL so I had only one option.
I went with EL34 because Tubelabs simulation list http://tubelab.com/designs/tubelab-sse/applications/.
The 6L6 I have are 6L6GC rated for higher voltage. I will give EL34 some time before rolling.
I am very interested in alternative tubes for my settings. Please let those tips coming.
I have only longterm experience with one tube amp before, VSi60, which was to strong for my speakers. This one I think is way better.
My OPT can not do UL so I had only one option.
I went with EL34 because Tubelabs simulation list http://tubelab.com/designs/tubelab-sse/applications/.
The 6L6 I have are 6L6GC rated for higher voltage. I will give EL34 some time before rolling.
I am very interested in alternative tubes for my settings. Please let those tips coming.
Just finished my SPP build. I have had the SPP board for almost a year but in the last month got the motivation to finish the SPP build. Everything went well and worked the first time! Love the sound! Big thanks to George for all his efforts. This is my second tubelab build (have an SSE as well). I had some PP transformers laying around from a different build so I had to use them. Compared to my SSE build (Hammond 1628SEA output transforms), much better high frequency response. My SSE is quite dark sounding by comparison. Must be those Hammond transformers.
I found the input sensitivity rather high with NOS RFT ECC81 tubes. Put some old and used JJ ECC81s and they seem to work a better.
I found the input sensitivity rather high with NOS RFT ECC81 tubes. Put some old and used JJ ECC81s and they seem to work a better.
Finished a SSE (275_300). I've put whatever flexibility the board allows.
Thanks to Tubelab (George Anderson).
- Switch Sec. V - 275 & 300v (B+ upto 360v)
- UL/Triode Switch
- 4 bias levels to run different tubes (680R on board and 3300R, 1800R on the toggles)
- Switch between tube /solid-state rectifier
Thanks to Tubelab (George Anderson).
Attachments
I wonder why the rectifier tube is so close to the input tube. I'd have that sited nearer to the power transformer.
There have been so many Tubelab SPP's by now, I don't think there are any issues due to the rectifier placement.
That said, I preferred the aesthetics without the rectifier tube so uses diodes instead. @Steve Morley 's build had the rectifier and other PSU parts off-board, further away as you suggest.
That said, I preferred the aesthetics without the rectifier tube so uses diodes instead. @Steve Morley 's build had the rectifier and other PSU parts off-board, further away as you suggest.
Attachments
@itsikhefez
I just bought the boards and I am putting together info for the SPP and the TSE II.This is the SPP, right? Would you mind sharing some info on the build? The PS circuit & transformer you are using? I see they are Hashimoto. I have the catalog and I see PT150-160 HW 40-8 25-8? I searched here and there but the info is very spread out people are reporting different solutions for different issues and info hard to follow.
Thanks in advance.
PS Actually I scrolled up a few pages and I see the kind of transformers you used.. Any additional info is still welcome!
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Hey, this post which you found I assume has all the details:
https://www.diyaudio.com/community/threads/pictures-of-your-tubelab-amp.157491/post-6855247
It's pretty much the standard SPP build, except with diodes instead of tube rectifier, and the transformers are HW-25 and PT-150.
https://www.diyaudio.com/community/threads/pictures-of-your-tubelab-amp.157491/post-6855247
It's pretty much the standard SPP build, except with diodes instead of tube rectifier, and the transformers are HW-25 and PT-150.
It does not hurt to use Inrush Current Limiters, one of the Primary side of the power transformer and one on the secondary; this removes the surge at switch on. However the delay circuit is the time it takes the heaters to warm up, so it is normally a non-issue.
The B+ may be higher, so the transformer probably needs to be specified differently, or some solution used for dropping the B+, but within certain constraints the tubes are fairly tolerant of variations.
The B+ may be higher, so the transformer probably needs to be specified differently, or some solution used for dropping the B+, but within certain constraints the tubes are fairly tolerant of variations.
I use a CL-90 on the input side (120R, 2A), and a CL-140 on the secondary side (1.1A, 50R)
specifications
I suppose there might be a case for the ICL being capable of introducing some sag in the supply, since they are not running at 100% and the R depends on the current. Most of the resistance is before 25% of the current flow, the difference between 75% and 100% loading is just 0.3R.
I think this is the combination suggested by George, and I am happy with the way the amps come up gradually on power-on; noticeably the heaters. I have built two amps with silicon rectifiers and they also have a nice ramp up when switched on.
specifications
I suppose there might be a case for the ICL being capable of introducing some sag in the supply, since they are not running at 100% and the R depends on the current. Most of the resistance is before 25% of the current flow, the difference between 75% and 100% loading is just 0.3R.
I think this is the combination suggested by George, and I am happy with the way the amps come up gradually on power-on; noticeably the heaters. I have built two amps with silicon rectifiers and they also have a nice ramp up when switched on.