Trying to dodge the Mercury Magnetics upcharge, I've been looking at what might be good candidates. (This would be a scratch build, so particular physical fit wouldn't matter.)
I'm particularly curious that all the info on the output transformers has reported 20-30 watt ratings on amps with a pair of 6L6 tubes, and I'm not sure whether that's a full-bandwidth rating or whether a typical guitar OT rated the same would do.
Ampeg Portaflex iron suggestions?
Moderators: pompeiisneaks, Colossal
Re: Ampeg Portaflex iron suggestions?
I know nothing about them other than they exist:
http://www.fliptops.net/index.htm
Ampeg always was a clean sounding builder, you might want to lean towards the huskier larger bandwidth and wattage OTs, at least on the bass amps, or just get the clone from Flip-tops. OTs are a recurring issue with each build for me. You don't want to over spec for fear of sterile tone, or just excess weight and money, but you never know what kind of muddiness or lameness you might get from an underspecd OT. Many vintage Fender OTs are undersized but Leo knew how to hit the sweet spot and had the r&d budget to find it. Compare a 2X6L6 45W 20-20KHz hifi OT to a vibrolux OT, that Vibrolux OT would prolly be rated 20W in Hifi-land.
Problem for the DIY is you only get one shot at punching the chassis, assuming you want it to look nice and have to choose btwn buying a Tranny or not paying the con-ed bill this month. Be nice to be able to breadboard the amps first and have a couple different trannies to try. I mostly solve the issue by simply copying those that went before me - lame, I know.
http://www.fliptops.net/index.htm
Ampeg always was a clean sounding builder, you might want to lean towards the huskier larger bandwidth and wattage OTs, at least on the bass amps, or just get the clone from Flip-tops. OTs are a recurring issue with each build for me. You don't want to over spec for fear of sterile tone, or just excess weight and money, but you never know what kind of muddiness or lameness you might get from an underspecd OT. Many vintage Fender OTs are undersized but Leo knew how to hit the sweet spot and had the r&d budget to find it. Compare a 2X6L6 45W 20-20KHz hifi OT to a vibrolux OT, that Vibrolux OT would prolly be rated 20W in Hifi-land.
Problem for the DIY is you only get one shot at punching the chassis, assuming you want it to look nice and have to choose btwn buying a Tranny or not paying the con-ed bill this month. Be nice to be able to breadboard the amps first and have a couple different trannies to try. I mostly solve the issue by simply copying those that went before me - lame, I know.
Last edited by rp on Sun Oct 30, 2011 10:41 pm, edited 1 time in total.
Re: Ampeg Portaflex iron suggestions?
Hi , can you check here :
http://www.tubeampdoctor.com/en/shop_Transformators/
TAD has some PT/OT for ampeg
http://www.tubeampdoctor.com/en/shop_Transformators/
TAD has some PT/OT for ampeg
ampeg trannys
tube depot has a b-15 set they look like quality, but they aint cheap
Live , Love , Learn
Re: Ampeg Portaflex iron suggestions?
Have you got any idea what the specific requirements are for the iron? It would help a great deal to have some clarity on this, otherwise, we are guessing (unless one of us happens to know the answer).
Looking at the schematic for a B15-N (is that the correct model?), I'd guess it requires a PT 345-0-345 @ 250mA, 6.3V @ 3.2@ and 5V @ 1.9A. For the OT, a primary of 5K or 5.5K -- not at all sure of the primary, just going by "typical" pair of 6L6.
If you look at Edcor, they offer PT XPWR127-120 for $93, here: http://www.edcorusa.com/products/728-xpwr127_120.aspx but the problem is that it has no 5V supply. For an upcharge, they can add a 5V supply, but that's going to start to defeat the savings. You can probably troll eBait for a 5V transformer for the rectifier -- I'd guess you are looking at no more than $20 delivered; beware, old iron spec'd for 110V primaries will run above where you want it.
Edcor also has some OT choices like the CXPP100-MS-5K for $93, here: http://www.edcorusa.com/products/459-cxpp100-ms-5k.aspx
The problem I see with this sort of "freelancing" of transformers is that they will not deliver the same tone as a "proper" set. The Edcor iron will probably deliver excellent tone, just not B-15 tone. It might even be close, but there is no way of knowing and probably not.
Edcor will make to order if you have requirements to give them. They may even have B-15 plans on file. You should ask. You may find it is a whole lot cheaper than the $500 I think you must be looking at.
An alternative you might consider is to buy a used PT on eBay. It will take some careful hunting and a great deal of patience. There are almost always used organ transformers available for under $50 that will probably fill the bill. Take the $200 you save and invest in a proper OT. That is, IMO, going to be your critical spot in making the tone right.
eBay examples that might or might not be appropriate, but you'll get the idea:
http://www.ebay.com/itm/Triad-R-20A-Vin ... 2568a54d72
http://www.ebay.com/itm/Pair-Webster-Po ... 415de54571
http://www.ebay.com/itm/Vintage-Power-T ... 3a62fa58bf
Here is a classic organ transformer and should have plenty of juice:
http://www.ebay.com/itm/Power-Transform ... 23159a2701
Here is another place you might look for a suitable used PT http://www.oldradioparts.com/ but I don't think you'll find a beefy 200mA+ model there.
Good luck.
Looking at the schematic for a B15-N (is that the correct model?), I'd guess it requires a PT 345-0-345 @ 250mA, 6.3V @ 3.2@ and 5V @ 1.9A. For the OT, a primary of 5K or 5.5K -- not at all sure of the primary, just going by "typical" pair of 6L6.
If you look at Edcor, they offer PT XPWR127-120 for $93, here: http://www.edcorusa.com/products/728-xpwr127_120.aspx but the problem is that it has no 5V supply. For an upcharge, they can add a 5V supply, but that's going to start to defeat the savings. You can probably troll eBait for a 5V transformer for the rectifier -- I'd guess you are looking at no more than $20 delivered; beware, old iron spec'd for 110V primaries will run above where you want it.
Edcor also has some OT choices like the CXPP100-MS-5K for $93, here: http://www.edcorusa.com/products/459-cxpp100-ms-5k.aspx
The problem I see with this sort of "freelancing" of transformers is that they will not deliver the same tone as a "proper" set. The Edcor iron will probably deliver excellent tone, just not B-15 tone. It might even be close, but there is no way of knowing and probably not.
Edcor will make to order if you have requirements to give them. They may even have B-15 plans on file. You should ask. You may find it is a whole lot cheaper than the $500 I think you must be looking at.
An alternative you might consider is to buy a used PT on eBay. It will take some careful hunting and a great deal of patience. There are almost always used organ transformers available for under $50 that will probably fill the bill. Take the $200 you save and invest in a proper OT. That is, IMO, going to be your critical spot in making the tone right.
eBay examples that might or might not be appropriate, but you'll get the idea:
http://www.ebay.com/itm/Triad-R-20A-Vin ... 2568a54d72
http://www.ebay.com/itm/Pair-Webster-Po ... 415de54571
http://www.ebay.com/itm/Vintage-Power-T ... 3a62fa58bf
Here is a classic organ transformer and should have plenty of juice:
http://www.ebay.com/itm/Power-Transform ... 23159a2701
Here is another place you might look for a suitable used PT http://www.oldradioparts.com/ but I don't think you'll find a beefy 200mA+ model there.
Good luck.
Re: Ampeg Portaflex iron suggestions?
When I built my B-18N/B-15ND I used a Hammond Power 278X and a 1650N equivalent built by Heyboer. If you don't know a B-18 is a 50W amp using a pair of 7027A's and a 7199 in the PI.
Original B-15's use a 150ma PT and a 35W audio output transformer. If it were me I would use a 273BX and a 1650HA or 1650G. You'll have plenty of current and output bandwidth.
Original B-15's use a 150ma PT and a 35W audio output transformer. If it were me I would use a 273BX and a 1650HA or 1650G. You'll have plenty of current and output bandwidth.
Re: Ampeg Portaflex iron suggestions?
If the 273BX is it, then that Triad R20A will make a great choice if you can get it for $50, including shipping. Much more than that, IMO, you will be getting too close to the retail price of the Hammond, and that makes it not worth the risk. Good luck!