1960 CF Martin + wanted

[capnjuan]

The Tonequest/Clarksdale re-issue, discussed Here and linked on the first page of this thread. The article says that the transformers shown below - made by Mercury Magnetics - are dupes of the original Martins...

Does anyone know what the primary impedance is on the tranny for the RT15/112? Also the tranny on the RT5/110 is larger than normal as well, is it gapped for single ended use, or is it an oversize PP put into single ended operation?...

Hi Eric; as noted above, you might try contacting Mercury Magnetics or Clarksdale ... see what they said about impedance.

Not completely sure but if an OT is built for P/P use, it has a center tap ... and SE transformers don't. So, I'm not sure that a P/P-CT transformer could work in SE configuration unless you connected the DC at the center tap, connected one B+ leg to the output tube's plate, and taped off the other side. Although it might work that way, I can't think of why it would be a good idea ... subbing a more expensive transformer for a less expensive one although, if it did work, it might sound pretty good ... but then so might a beefier SE transformer. :? Best wishes, J

 

[Jefemaximo]

Great thread gents. Thanks for all the good info. I have been chasing one of these amps for about a year and finally got one this week. I now have a DeArmond R5T. I was looking for one the larger versions - branded either Martin or DeArmond - but this one is just fine. It really is the little mouse that roared. So much sound out of such a small amp. Plus, the overdrive and crunch it produces at higher volumes is very impressive. I see that there is another (larger) one on eBay right now for stupid money. In this economy, it will be a stretch for someone to pay $2,500, but you never know. As much as I like this little amp, I will most likely be putting it up on eBay soon. I already have a great tube amp, and I can put any proceeds from the sale toward a new guitar! Still thinking about this though.....

 

[ce blues]

Capn' Juan,

I agree with you about the use of a P/P OT xfmr with a center tap not really working in a single ended amplifier. If is has a CT, it is designed for push pull operation: feeding the B+ to the CT and powering each side of the P/P design with the blue and brown leads. Let me, rephrase that, I don't think it would be workable.... I sure as heck haven't seen it all.
blue

 

[capnjuan]

Hi blue; whether something would work and whether it's a good idea are two different things. In a P/P-CT transformer, one side is cut off while the other is inducing a signal on the secondary so taping off one plate supply lead wouldn't hurt anything. Weber, Hammond, and other after-market SE OTs aren't especially expensive; so 'burning' a better grade P/P OT on an SE project means that if/when a better application for the P/P OT comes along, it's going to be coming out of there anyway. And then there's the impedance-matching question. I think the biggest appeal is getting the bigger iron in play ... the Weber / Hammond OTs aren't that large and, as suggested above, sometimes bigger is better and burning a P/P transformer, assuming impedance-matching, would probably work ... probably. CJ

 

[ce blues]

Thanks Capn'.... that's why I qualified my statement at the end. I realized that the possibility of my being full of ripe and rich caca, had a high probability. Many years of having to use a crowbar to remove my foot from my mouth have taught me to make statements like that with caution... my experience is limited to 3 builds from chassis upwards (1 SE and 2 P/P amps) and repairs on quite a few more amps.

my pop was an old school electronics technician (had a TV shop from the 50s to early 70s... he refused to jump on the solid state band wagon--I think he was too prideful to go back to school, perhaps he feared the "new" electronics would be too mysterious or beyond his mind-set/age [the old dog, new tricks syndrome].... I inherited much of his shop equipment (as did my brother, who got the lion's share because he had the university electronic engineering degree...whereas, I was just a guitar bum keeping me and my mates gear running hot and true...mostly blackface Fenders, Ampeg bass amps and the like....Blackfaces are too much fun to work on). I wish I had taken more advantage of the old man as a resource when he was alive and still able to think... oh well, spilt milk etc.

thanks for straightening me out on that issue.

blue

 

[capnjuan]

Hi Blue ... I've gotten my foot stuck a few times too ... what do they call that ... insertion loss? I got my start in vacuum tube audio in the '80s; buying/repairing/blowing up/trading up old HK, Fisher, Dynaco components, integrated amps, and receivers. We moved here to FL in 1993 and for the sake of saving floorspace, I gave up my system which by then included a AR D76 (4 KT66s), PS Audio 2 bass amplifier each feeding into a pair of bi-wired Vandersteen 2CIs, a Marantz 7C preamp with regulated supply, a 21-tube Marantz (O-Scope) 10B tuner, and a hot-rodded Magnavox 2040 CD player with a stupidly expensive set of caps hanging on the legs of the DAC. It wasn't the world's best system but it was painful to let it go.

Thereafter, I lost interest in vacuum tube electronics until a few years ago when my rejuventation project was a '80-'82 Fender 75 like this one on eBay. Since then, I've pretty much settled in on the warm, throaty, slightly grungy tone of tweed Gibson amps including a GA1RT, GA8 Gibsonette, GA18, GA19RVT, Two GA20Ts, and a GA30RV. And just to show that my loyalties are in the right place, a Guild T1 RVT and a Guild 8417 head converted to 6L6s. These projects have ranged from DOA to near-mint and I prefer buying/rehabbing/turning over to scratch-building ... probably has something to do with not wanting to surround myself with my mistakes ... :wink: J

 

[Jefemaximo]

Post deleted

 

[capnjuan]

Martin DeArmond R15T on eBay Just the one pic; sellers says it's 15 watts ... 6V6s? No public domain schematic although there is one attached inside the amp.

 

[Brown-Recluse]

More pictures have been added to the listing. It started out with an opening bid amount of $1800.00 and $300.00 for UPS ground shipping. Then the shipping went down to $200.00 and the opening bid amount remained at $1800.00. Now the opening bid amount has been increased to $1900.00.

It is extremely clean and not unreasonably priced if compared to the price of an original Tweed Deluxe or one of the Tone Quest Clarksdales. I feel kind of sorry for the Goodwill store that this amp was on its way to before it was "caught just in time for some lucky musician to come along and buy this amazing amplifier."

The tube compliment is the same as the corresponding Martin 112T: (2) 6v6, (3) 12AX7, (1) 5Y3. The amp's schematic is propbably on the inside of the instruction sheet paperwork, not inside of the amp. The tube chart is attached to the inside of the cabinet on these amps.

Here is one that failed to receive any bids earlier this month: http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWAX:IT

 

[capnjuan]

Hi BR and thanks for the note about the updated auction; I don't follow these amps much past what I've posted here but I don't recall ever seeing a DeA; black cosmetics or this brown, in as good condition as this auction amp. The previous amp ... too bad about all the pitting on the control panel and could understand why people who are interested in these would pass ... but this one ... think it might bring $3,000? J

 

[jakers]

Here's a surprise: I seached the completed listings on ebay; The R15T apparantly sold for $7601! Is this for real?
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... K:MEWAX:IT

 

[capnjuan]

Apparently so ... I thought it was astonishing too. It's collector behavior; guitars or amps ,,, it's what accounts for $50,000 Les Pauls ... and $1,000 tweed amps that sell for $7,500.

 

[dklsplace]

Well I guess that tears it......I've been contemplating the desire to keep mine, versus the good that could come to the family right now if I decided to sell. Tis the season I suppose.

 

[Default]

Youch! I feel your pain. I keep looking at the AJ and thinking what I could get for it, but we're not hurting at the moment.

 

[capnjuan]

Well I guess that tears it......I've been contemplating the desire to keep mine, versus the good that could come to the family right now if I decided to sell. Tis the season I suppose.

... sometimes you have to cash your good fortune in ... exchange it for some more down the road ... J

 

[guildzilla]

The auction result on that DeArmond amp is a jaw-dropper. Holy moly.

Sometimes this stuff is worth selling more than it's worth keeping. Personally, Don, I'd go for the gusto.

 

[Default]

We have a Thomas Norton clock. It was repaired in 1811. I've only seen a couple mentioned and am terrified to find out what it might be worth.

 

[dklsplace]

Finally broke down & listed. I've had A Reverend Alltone installed so putting the Jenson back in gave me a chance to take some more pictures & clean a little dust.

 

[guildzilla]

Such a gorgeous relic. Best luck, Fearless Leader!

I, Boris, have placed the first bid (just for kicks).

 

[capnjuan]

Good luck Don; it's a beauty!