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Best parts for 45 tube amp

Searching for the output transformer I have came across this OPT list:

Tribute
Tamura
Lundahl = James = Hashimoto = Tango = O-netics
Bartolucci = Audio Note
Electraprint
Magnequest
Hammond

What do you think about it? Are the Tribute transformers the best? Which one should I choose? I would like to build the amp and don't do any additional changes later (maybe just caps or resistors), so I would like to get the best possible parts now.
 
Maybe I missed it but you haven't mentioned how much previous experience you have with electronics. Have you built or repaired anything in the past?

I mentioned that the Bugle 45 was my first DIY build but I had previously restored several vintage tube amps. If you're new to working on electronics you might consider taking a similar path. Find an inexpensive console pull and rebuild it. If you can find one locally it can be quite inexpensive. I've found several old consoles, Magnavox mostly, for under $40. There's lots of good info on here on how to rebuild them.

If you have no experience and want to jump into the deep end I'd suggest that going with the Tubelab board would be your best bet since it's more kit-like.
 
FlaCharlie said:
Maybe I missed it but you haven't mentioned how much previous experience you have with electronics. Have you built or repaired anything in the past?

I mentioned that the Bugle 45 was my first DIY build but I had previously restored several vintage tube amps. If you're new to working on electronics you might consider taking a similar path. Find an inexpensive console pull and rebuild it. If you can find one locally it can be quite inexpensive. I've found several old consoles, Magnavox mostly, for under $40. There's lots of good info on here on how to rebuild them.

If you have no experience and want to jump into the deep end I'd suggest that going with the Tubelab board would be your best bet since it's more kit-like.
Click to expand...

Yes you are right. I have not previous experience with building electronics and point to point is little bit scary for me and Tubelab has really great info on websites so I will give it a try.

But since I will be trying to build board based project I would like to choose best components right away. Could you please recommend best transformer manufacturer from above posted list (or any other if there is better one), thank you.

Also I have been recommended AudioNote resistors and Mundorf Caps for the project...any comments on that, are there any better options?
 
martin15560 said:
Yes you are right. I have not previous experience with building electronics and point to point is little bit scary for me and Tubelab has really great info on websites so I will give it a try.

But since I will be trying to build board based project I would like to choose best components right away. Could you please recommend best transformer manufacturer from above posted list (or any other if there is better one), thank you.

Also I have been recommended AudioNote resistors and Mundorf Caps for the project...any comments on that, are there any better options?
Click to expand...

I have no experience with any OTs from those manufacturers since I've always used transformers pulled from vintage gear. That said, there is no "best transformer manufacturer". Everyone has different preferences. Each manufacturer has numerous different models so unless someone has compared OTs designed to be used with 45s in an SET circuit, preferably the one you're considering building, any comparison is of limited value. Same goes with boutique parts. And it's important to realize that everybody listens to OTs or cap choices on different speakers, with different sources, in different rooms and, most importantly, with different ears.

I would spend some time reading about other people's experiences with the Tubelab board before spending a bunch of money on parts. I believe there is a Tubelab forum on DIY Audio, right?

But, again, if you have no experience whatsoever it would be a good idea to start with something you can learn on. Here's a thread about Dave Gillespie's mod of a SE Magnavox that gets rave reviews.

http://www.audiokarma.org/forums/in...ore-out-of-the-8600-series-a-lot-more.665735/

The unrestored Magnavox amps are fairly easy to find on eBay and if you're lucky and patient you might find one locally in an unwanted console. When finished, the amp will have similar power output, maybe a bit more, than a 45. You can build one for less than the cost of a single, high-end, OT. Heck, probably less than some boutique caps.

A fairly simple project like this, where you don't need to build a chassis, will allow you to learn basic skills like how to solder and measure voltages safely, before you start something more ambitious.
 
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FlaCharlie said:
I have no experience with any OTs from those manufacturers since I've always used transformers pulled from vintage gear. That said, there is no "best transformer manufacturer". Everyone has different preferences. Each manufacturer has numerous different models so unless someone has compared OTs designed to be used with 45s in an SET circuit, preferably the one you're considering building, any comparison is of limited value. Same goes with boutique parts. And it's important to realize that everybody listens to OTs or cap choices on different speakers, with different sources, in different rooms and, most importantly, with different ears.

I would spend some time reading about other people's experiences with the Tubelab board before spending a bunch of money on parts. I believe there is a Tubelab forum on DIY Audio, right?

But, again, if you have no experience whatsoever it would be a good idea to start with something you can learn on. Here's a thread about Dave Gillespie's mod of a SE Magnavox that gets rave reviews.

http://www.audiokarma.org/forums/in...ore-out-of-the-8600-series-a-lot-more.665735/

The unrestored Magnavox amps are fairly easy to find on eBay and if you're lucky and patient you might find one locally in an unwanted console. When finished, the amp will have similar power output, maybe a bit more, than a 45. You can build one for less than the cost of a single, high-end, OT. Heck, probably less than some boutique caps.

A fairly simple project like this, where you don't need to build a chassis, will allow you to learn basic skills like how to solder and measure voltages safely, before you start something more ambitious.
Click to expand...

I know how to measure voltage and solder...I just haven't done any larger project...I will start with tubelab (and hope for the best :D) since I don't really want to build more than one amp.
 
This mess was the breadboard of the RH84 SEP 6BQ5/EL84 amplifier circuit, using James universal output transformers with the 5K primary taps. (wished they still made said OPTs)
I was experimenting with cathode bypass using polyprop capacitors, and old oil caps for other filtering.

It was one of the best sounding single-ended 6BQ5 amplifier circuits on my Klipsch Cornwalls to my ears, those James OPTs really helped.
A good SEP 6BQ5/EL84 amplifier (with real good iron) can be a poor man's triode amp...



index.php
 
I am thinking about what resistors and capacitors to choose. I am considering to use metal film Vishay resistors (because of the low level of distortion), what do you think about them?


And probably one of these capacitors:
Mundorf Supreme SilverGold Oil
V-cap CuTF
Jupiter Copper Foil Paper & Wax,
Intertechnik Audyn True Copper MAX
Miflex KCPU-01
Rike Audio Q-CAP
Duelund Cast Cu Sn

I have found most information about the Mundorfs, do you have some experience with the other one. Which caps would you recommend?
 
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If you are going to go with the tubelab board read every page about it on the site. Several times. You will have to do a bit of hunting for a couple of the parts. Some subs are listed. Also read through the thread over at DIY forum. Somewhere in the thread he lists the Hammond transformer he used in the end. You can email him also. I'll try to find my notes and get the number. One thing that is very important is the 5 volt regulator for the heaters. It runs at pretty much max current. Use a large TO-220 type. I used a tall finned aluminum heat sink mounted on the chassis plate and ran wires from the board to the regulator on the heatsink. If it overheats it will shut down. I ordered an extra just in case it fails.I've used the amplifier regularly for a couple years without issue so far though.
 
I will read the Tubelabe pages again. I would just like to use MF resistors, are Vishay's good?
And change caps (at least C4 and C5 but at best all of them). But I don't want to experiment too much. I will use Mundorf if there is noone who would be using other posted brands with good results.
 
Lavane's advice is the best you are going to get. Read and reread the tubelab site as there is a lot of detail, sometimes not in logical places...

Overall, the use of particular caps and resistors is a very personal thing, use the correct value, fits the location, what works for your budget, and also what will make the "what if I used *some other cap* concerns minimal.

The only positions where you are likely to use film/PIO caps are the coupling caps between the 5842 and the outputs, C9 and C11 and the auxiliary cap across C5 if you decide to use it. For the C5 auxiliary cap I used the Temco 100uf motor run cap that can be found on ebay based upon the advice of threads on Diyaudio. My SE started out with Obligato Gold coupling caps cause I happened to have a pair in the correct value, but I eventually swapped them out for Russian PIO K40-9y caps. I did not notice much of a difference. Which was expected as George mentions it on his web page.

Vishay metal film resistors are fine. I have used them, KOA Spear, Stackpole any many others in my projects. It is important to note that R31 and R32 (4.7k) grid stopper resistors should ideally be carbon comp to help tame the 5842 from oscillating.
 
I used good ol cheap Solen's for coupling caps. I use them a lot. In crossovers as well.
Other than coupling caps I used what was listed on the parts list. I wouldn't get too hung up on fancy resistors or lyrics. The thing was dead quiet even spread all over the bench connected up with jumper wires. The trany I used was a Hammond 272JX. I know Edcor has a part number for one someone had them build for this amplifier. I lost the link though when an old pad died. Someone chimed in with the part number but that thread was lost a couple years ago.
 
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Edcor Iron I used in my first build was XPWR131-GXSE10-5k. Generally doesn't take as long to build as Edcor site states.
 
mkane said:
Edcor Iron I used in my first build was XPWR131-GXSE10-5k. Generally doesn't take as long to build as Edcor site states.
Click to expand...

Ok so I will use XPWR131 as power transformer and probably Electra Print for OTs so far.

One thing I still don't know, if I build the amp with parts from Tubelab list, what is standart voltage? The 45 tubes are max. for 275V so if I want voltage around 280V do I need to do some changes e.g. in caps specs? I am asking because I saw posts saing there are people running Tubelab board on 320-330V.
And if I get to 280V is it OK to keep R14, R25 resistors on 20K or do I need higher value (there is 30K value in notes on Tubelab pages for voltage over 300V...in schematic there are 20K resistors but I don't know for which voltage).
 
Standard spec parts work fine. When you purchase parts it doesn't hurt to order a few extra resistors just in case.
 
Something i may look into is the SE boards could stand a bit more support in the middle IMO. I may attempt to drill a hole or to so I can have additional standoffs near the center. I asked a bazillion questions on the Tubelab site during my first build, the 2nd build went without a hitch.

I never finished the base on this. I tried to use automotive wax, not knowing anything about wood finishes.

DSC_0667.JPG DSC_0668.JPG
 
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